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1
Lei, Fan, and Chuhua Zhang. "Preliminary Optimization of Multi-Stage Axial-Flow Industrial Process Compressors Using Aero-Engine Compressor Design Strategy." Applied Sciences 11, no. 19 (October 5, 2021): 9248. http://dx.doi.org/10.3390/app11199248.
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Aero-engine core compressor preliminary design strategy has been successfully applied to the advanced design of gas turbines compressors. However, few researchers have addressed the application of the aero-engine core compressor preliminary design strategy in the preliminary optimal design of industrial process compressors. Here we embedded the aero-engine core compressor preliminary design strategy into a preliminary optimal design method, in which six types of design parameters widely used to define the aero-engine compressor configuration, i.e., aspect ratio, solidity, reaction, rotation speed, outlet axial Mach number, and inlet radius ratio, were used as the design variables. The 4-stage, 5-stage, 6-stage, and 7-stage compressor configuration with the same overall design requirements for a large-scale air separation main compressor were preliminarily optimized by the developed method, in which the 4-stage design has a stage pressure rise level of current aero-engine core compressors, whereas the 7-stage design has that of current industrial process compressors. The optimized compressor configurations were then refined with the throughflow-based detailed design method and finally verified with computational fluid dynamic simulations. It is found that the developed method can optimize design efficiency and accurately predict aerodynamic performance of compressors in a few minutes. Several design guidelines for the advanced industrial process compressors were also identified. This work is of significance in extending aero-engine core compressor design strategy to the design of advanced industrial process compressors.
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Li, Ting, Yuchuan Wang, Xiuli Mao, Diyi Chen, Rui Huang, and Quanke Feng. "Development and Experimental Study of the First Stage in a Two-Stage Water-Flooded Single-Screw Compressor Unit for Polyethylene Terephthalate Bottle Blowing System." Energies 13, no. 16 (August 16, 2020): 4232. http://dx.doi.org/10.3390/en13164232.
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The oil-free compressor is a key component in fabricating polyethylene terephthalate (PET) bottles for beverages and water. At present, the main compressor type used for blowing PET bottles is the reciprocating compressor. However, compared to screw compressors, reciprocating compressors have shortcomings of high energy consumption and too many consumable parts. Many manufacturers of PET bottles in Asia are seeking to replace reciprocating compressors with screw compressors, as we know. Screw compressors can be classified as single-screw compressors (SSC) and twin-screw compressors. Since the load in a twin-screw compressor is far larger than that in an SSC, SSCs are more suitable for being developed for high-pressure applications such as PET bottle blowing. This paper presents a performance study on an oil-free single-screw compressor as the first stage of the PET compressor unit. A 5.4 m3·min−1 prototype and its test rig were developed. The thermophysical process of the moist air is theoretically analyzed. The pressure loss on the flow path and the influence of the important parameters are experimentally investigated. It is found that water vapor cannot be separated during the adiabatic compression process. The results also show that the pressure loss from the discharging duct to the check valve accounts for the largest percentage of the total pressure loss. The experimental results further show that the discharge capacity and shaft power increase almost linearly with the motor speed. The efficiency declines with increasing injected water temperature. The discharge capacity and shaft power all increase with the injected water flowrate, and an optimum flowrate is found to ensure a highest isentropic efficiency. With the increase in discharge pressure, the discharge capacity decreases, and the shaft power increases. The isentropic efficiency is found to have its maximum value at a certain discharge pressure.
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Song, T. W., T. S. Kim, J. H. Kim, and S. T. Ro. "Performance prediction of axial flow compressors using stage characteristics and simultaneous calculation of interstage parameters." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 215, no. 1 (February 1, 2001): 89–98. http://dx.doi.org/10.1243/0957650011536598.
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A new method for predicting performance of multistage axial flow compressors is proposed that utilizes stage performance curves. The method differs from the conventional sequential stage-stacking method in that it employs simultaneous calculation of all interstage variables (temperature, pressure and flow velocity). A consistent functional formulation of governing equations enables this simultaneous calculation. The method is found to be effective, i.e. fast and stable, in obtaining solutions for compressor inlet and outlet boundary conditions encountered in gas turbine analyses. Another advantage of the method is that the effect of changing the angles of movable stator vanes on the compressor's operating behaviour can be simulated easily. Accordingly, the proposed method is very suitable for complicated gas turbine system analysis. This paper presents the methodology and performance estimation results for various multistage compressors employing both fixed and variable vane setting angles. The effect of interstage air bleeding on compressor performance is also demonstrated.
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Hönen, H. "Axial Compressor Stall and Surge Prediction by Measurements." International Journal of Rotating Machinery 5, no. 2 (1999): 77–87. http://dx.doi.org/10.1155/s1023621x9900007x.
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The paper deals with experimental investigations and analyses of unsteady pressure distributions in different axial compressors. Based on measurements in a single stage research compressor the influence of increasing aerodynamic load onto the pressure and velocity fluctuations is demonstrated. Detailed measurements in a 14-stage and a 17-stage gas turbine compressor are reported. For both compressors parameters could be found which are clearly influenced by the aerodynamic load.For the 14-stage compressor the principles for the monitoring of aerodynamic load and stall are reported. Results derived from a monitoring system for multi stage compressors based on these principles are demonstrated. For the 17-stage compressor the data enhancement of the measuring signals is shown. The parameters derived from these results provide a good base for the development of another prediction method for the compressor stability limit. In order design an on-line system the classification of the operating and load conditions is provided by a neural net. The training results of the net show a good agreement with different experiments.
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Kosuri, Lakshmi Thirumala, M. Deepika Krishna, Adilakshmi i. Karapat, B. S. B. Ayyappa Swamy, and Dinesh Nayak S. "A Low Power High Speed Accuracy Controllable Approximate Multiplier Design." International Journal for Research in Applied Science and Engineering Technology 10, no. 4 (April 30, 2022): 1625–30. http://dx.doi.org/10.22214/ijraset.2022.41617.
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Abstract: For energy effective and high performance design, the low power VLSI circuit is used. Multiplier is an essential part of low power VLSI design, since the effectiveness of the digital signal processor depends upon the multiplier. In multiplier circuit, utmost of the power is dissipated across in full adder circuits. Multiplication is one of the important process in microprocessor and there will be a lot of delay because of array multiplier, which can be compressed with the help of the column compressor approach. It uses a selection of half adders, full adders and compressors to sum the partial products in stages until two numbers are left. An 8 * 8 and 16 * 16 bit multiplier design is executed by assigning the adder and compressor. Partial product totality is the speed limiting operation in multiplication due to the propagation detention in adder networks. In order to reduce the propagation detention, compressors are introduced. Compressors calculate the sum and carry at each position concurrently. The attendant carry is added with a advanced significant sum bit in the coming stage. This is continued until the final product is generated. The partial product tree of the multiplier is estimated by the proposed tree compressor ( High Speed Compressor, Dual Stage Compressor, Exact Compressor). Keywords: Partial Products, Half Adder, Full Adder, High Speed Compressor, Dual Stage Compressor, Exact Compressor.
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Qi, Zhaogang, Jun Yang, Jiangping Chen, Haifeng Zhang, and Li Zhang. "Experimental investigation on a two-stage CO2 compressor with high back pressure." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 7 (November 10, 2011): 1811–20. http://dx.doi.org/10.1177/0954406211428245.
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In this article, two samples of two-stage rolling piston CO2 compressors with and without intercooler are developed and experimentally studied. These CO2 compressors are high back-pressure compressors, which mean the pressure inside compressor shell is the discharge pressure of the second stage. A test rig was designed to measure the performance and efficiency of this compressor. The test results show that the suction vapor temperature at the second stage inlet pipe has few influences on the performance and efficiency of the first compressor sample with intercooler. The volumetric efficiency linearly decreases with the increase of compression ratio of the suction and discharge pressure, and the volumetric efficiency can maintain in a relative constant range during a wide compression ratio changes in this high back-pressure design. There exists an optimum compression ratio for each suction pressure at the first stage, where the compressor isentropic efficiency is maximum. A generalized volumetric efficiency correlation for two-stage CO2 rolling piston compressor as a function of compression ratio is proposed and it can describe 100% of the test data within ±5.0% with a mean deviation of 1.7%. This would be helpful as a guide for designing such type compressor.
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Hamersztein, A., A. Davidesko, and N. Tzabar. "Numerical optimization of a multistage sorption compressor." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012113. http://dx.doi.org/10.1088/1742-6596/2116/1/012113.
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Abstract Sorption compressors are driven by thermal cycles and have no moving parts, excluding some passive check valves. Such compressors are suitable for powering Joule-Thomson (JT) cryocoolers and can provide reliable and vibration free active cooling system with a potential for high reliability and long operating life. The thermal cycle consists of cooling and heating a sorbent material which is installed in a sorption cell, where the heating is obtained by an inner electric heater and cooling is obtained by the surrounding via the sorption cell envelope. The investigation and optimization of the sorption cells were conducted in previous work, at steady state conditions, by a one-dimensional heat and mass transfer numerical model. The current paper presents a dynamic numerical model of sorption compressors which consist of several sorption cells. The numerical model allows one to three compression stages, with any number of sorption cells at each stage. The model enables the investigation of dimensional parameters and operational parameters, and provides the low and high pressures, pressure fluctuations, and compressor’s efficiency. The current investigation focuses on a three-stage compressor for nitrogen, with low and high pressures of 0.2 and 8 MPa, respectively, and a mass flow rate of about 11 mg/s.
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Dalbert, P., B. Ribi, T. Kmeci, and M. V. Casey. "Radial compressor design for industrial compressors." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 1 (January 1, 1999): 71–83. http://dx.doi.org/10.1243/0954406991522194.
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Industrial centrifugal compressors have a very large field of applications in chemical, petrochemical and gas transport applications with an enormous variety of gases, pressure levels and suction volumes. This paper describes the special design features of this type of compressor and sheds light on a method of standardization to overcome the large diversity of machine types. It reviews the aerodynamic and thermodynamic aspects in the design of impellers and diffusers, discusses the importance of the stage matching and illuminates the effect of stage components on stability.
9
Giannissis, G. L., A. B. McKenzie, and R. L. Elder. "Experimental Investigation of Rotating Stall in a Mismatched Three-Stage Axial Flow Compressor." Journal of Turbomachinery 111, no. 4 (October 1, 1989): 418–25. http://dx.doi.org/10.1115/1.3262289.
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This paper reports on an examination of rotating stall in a low-speed three-stage axial flow compressor operating with various degrees of stage mismatch. The objective of this study was to simulate the mismatching that occurs in high-speed multistage compressors when operating near surge. The study of the stall zones involved the use of fast response measurement techniques. The study clearly shows how stages can operate in an axisymmetric fashion even when heavily stalled, since rotating stall inception requires the stall of more than one stage. The study also compares conditions required for full-span and part-span stall and suggests that the part-span stall structure is more relevant to high-speed multistage compressors.
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Rekstin, A., V. Semenovskiy, K. Soldatova, Y. Galerkin, and K. Sokolov. "The simulation of gas-dynamic characteristics of centrifugal compressors in turbo-expander units." E3S Web of Conferences 124 (2019): 01008. http://dx.doi.org/10.1051/e3sconf/201912401008.
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Prof. Y. Galerkin and his team have developed and completed designs of 19 single-stage centrifugal compressors for turbo-expander packaged units applying Universal Modeling Method for the company “Turbokholod JSC” since 2005. The most powerful compressor is 6500 kW. The highest delivery pressure is 12 MPa. One hundred fifteen turbo-expander packaged units with total capacity 400 000 kW were manufactured, installed and were in operation in December 2018. The gas-dynamic characteristics of compressors comply with technical specification when operated within given range of initial temperatures and initial and final pressures up to 16 combinations for some compressors. The dimensionless characteristics of the compressor stages vary within the range of design parameters: flow rate coefficient 0.0278-0.0697, loading factor 0.43-0.71. The simulation of gas-dynamic characteristics of one of the designed compressors by the newest version of mathematical model is presented as an example, demonstrating the simulation features and effectiveness.
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Galerkin, Yuri, Aleksey Rekstin, Aleksandr Drozdov, Kristina Soldatova, Olga Solovyeva, and Elena Popova. "The optimal gas dynamic design system of industrial centrifugal compressors based on Universal modeling method." E3S Web of Conferences 178 (2020): 01028. http://dx.doi.org/10.1051/e3sconf/202017801028.
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We present the modern stage of development of Universal Modeling Method, a complex of mathematical models and software for optimal design of centrifugal compressors - a new version of simplified mathematical model of efficiency and new software for variation calculations of multistage compressors. Based on this numerical calculation complex we have created a method for preliminary design of flow paths of stages - 2D and 3D impellers, vane and vaneless diffusers and return channels. The new, 9th version of its mathematical model features a quasi-3D calculation method of 2D and 3D impellers design, a new principle of pressure characteristic calculation, a new model of vaneless diffusers and much more. “Digital twin of a centrifugal compressor stage” and “3D compressor” software create digital descriptions of the flow part and its solid model (“digital twin”).
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Kozhukhov, Yuri, Serafima Tatchenkova, Sergey Kartashov, Vyacheslav Ivanov, and Evgeniy Nikitin. "Research of a Spatial Flow of a Low-Flow Stage of a Svd-22 Centrifugal Compressor by Computational Fluid Dynamics Methods Using Super-Computer Technologies." E3S Web of Conferences 220 (2020): 01082. http://dx.doi.org/10.1051/e3sconf/202022001082.
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This paper provides the results of the study of a spatial flow in a low-flow stage of a SVD-22 centrifugal compressor of computational fluid dynamics methods using the Ansys CFX 14.0 software package. Low flow stages are used as the last stages of multistage centrifugal compressors. Such multistage compressors are widely used in boosting compressor stations for natural gas, in chemical industries. The flow features in low-flow stages require independent research. This is due to the fact that the developed techniques for designing centrifugal compressor stages are created for medium-flow and high-flow stages and do not apply to low-flow stages. Generally at manufacturing new centrifugal compressors, it is impossible to make a control measurement of the parameters of the working process inside the flow path elements. Computational fluid dynamics methods are widely used to overcome this difficulties. However verification and validation of CFD methods are necessary for accurate modeling of the workflow. All calculations were conducted on one of the SPbPU clusters. Parameters of one cluster node: AMD Opteron 280 2 cores, 8GB RAM. The calculations were conducted using 4 nodes (HP MPI Distributed Parallel startup type) with their full load by parallelizing processes on each node.
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Gulbala Alasgarov, Gulbala Alasgarov, Alovsat Baghirov Alovsat Baghirov, and Shahriyar Baghirov Shahriyar Baghirov. "DIAGNOSTICS OF THE OPTIMAL OPERATING MODES OF GAS TURBINE COMPRESSOR STATIONS BASED ON THE ANALYSIS OF TECHNOLOGICAL PROCESSES." PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 12, no. 01 (January 22, 2022): 14–28. http://dx.doi.org/10.36962/pahtei1201202214.
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The article is dedicated to the analysis of the influence of the seasonally changing ambient temperature on the technological parameters of the compression process at a gas turbine compressor station for the transportation of natural and associated gas collected from oil and gas fields by an offshore subsea gas pipeline. As a result of the analysis, indicators of suction and discharge pressure, compressor capacity, ambient temperature during the summer and winter months were collected at each stage of a multi-unit two-stage compressor station. The indicators were divided into intervals, the number of measurements in the interval was determined, and graphs of the dependence of the number of measurements on the average value of the interval were built. As a result of the analysis of the graphs, the complex influence of technological parameters and ambient temperature on the performance of gas turbine compressors was evaluated. To compare the results and study the effect of the parameters on the operating mode and efficiency of the compressor station, the numerical value of the criterion as the ratio of the maximum number of measurements to the average value of the corresponding interval for each parameter was calculated. For both 1st- and 2nd-stage compressors, the value of this criterion for productivity was found to be almost twice as low in winter compared to summer. For this reason, there is a need to develop measures that can ensure the operation of the compressor station in the optimal operating mode. As a result of the analysis, it was found that in the 1st stage gas turbine compressors, due to increase of the inlet pressure, which is a positive factor for the compressor, by 16.4% (from 58 psi to 67.5 psi) in summer compared to winter, and due to the increase of the outlet pressure, which is the negative factor, by 0.9% (from 285 psi to 288 psi) and an increase in ambient temperature of 36o F (from 42o F to 80.5o F), the productivity is decreased by 15.2% (from 40.15 MMSCFD to 34.05 MMSCFD) to). In 2nd-stage gas turbine compressors, due to no change of the inlet pressure, which is a positive factor for the compressor, in summer, compared to winter (273 psi in both cases), and due to the decrease of the outlet pressure, which is a negative factor, by 0.2% (from 807.5 psi to 805.5 psi. ) and an increase in ambient temperature of 36o F (from 42o F to 80.5o F), productivity decreased by 10.1% (from 49.05 MMSCFD to 44.05 MMSCFD). Thus, 10.1% of the 15.2% decrease in the productivity of gas turbine compressors in the summer season is due to the increase in ambient temperature, while the remaining 5.1% is due to the organization of technological processes. Taking into account this factor in the field, the selection of the correct technological mode in the gas transportation system allows to prevent the loss of large amounts of gas. Taking into account the design features of gas turbine compressor units, it is concluded that the 10.1% decrease in productivity in the 2nd stage gas turbine compressors in the background of the constant no-change of compressor inlet and outlet pressures in summer and winter is due to automatic decrease in RPM of gas turbines from nominal 15000 cycles/min and thus the decrease of the power of gas turbines due to the overload in summer. Considering the fact that each turbine consumes 30,000 m3 of fuel gas per day, the 360,000 m3 gas per day for fuel at the station is taken from the outlet of the 2nd stage gas turbine compressors, and these turbines are overloaded, the fuel gas is considered to be taken from another source. By feeding all the turbines of the station from the outlet of the 1st stage compressors, it is possible to reduce the load on the interstage collector of the station, increase the productivity of the 1st stage compressors and direct the gas compressed by the 2nd stage compressors to the whole outlet pipeline. As a result of this technological operation, an additional 200,000-250,000 m3 of gas per day can be transported through the compressor station. This technique is recommended for multivariate analysis of various technological processes. As a result of the study, a technological scheme was proposed for increasing the productivity of a gas turbine compressor station by 3-4% by changing the source of fuel gas extraction. Keywords: gas turbine, compressor, natural gas pressure, ambient temperature, productivity, fuel gas, statistical method.
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Seddigh, F., and H. I. H. Saravanamuttoo. "A Proposed Method for Assessing the Susceptibility of Axial Compressors to Fouling." Journal of Engineering for Gas Turbines and Power 113, no. 4 (October 1, 1991): 595–601. http://dx.doi.org/10.1115/1.2906282.
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Although the overall effect of compressor fouling on engine performance has been recognized for many years, remarkably little has been published on the quantifiable effects. Mathematical modeling of compressors using stage stacking methods has recently been used for a systematic study of compressor fouling and earlier investigations led to an interest in the effects of engine size and compressor stage loading. This paper presents a proposed index showing the susceptibility of compressors to fouling, which could be useful in helping operators to determine cleanup intervals. Three engines of widely differing performance were used in developing this index and additional operator experience would be useful in confirming its validity.
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Kalinkevych, M., V. Ihnatenko, O. Bolotnikova, and O. Obukhov. "Design of high efficiency centrifugal compressors stages." Refrigeration Engineering and Technology 54, no. 5 (October 31, 2018): 4–9. http://dx.doi.org/10.15673/ret.v54i5.1239.
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The modern trend in compressor industry is an extension of the use of multi-shaft centrifugal compressors. Multi-shaft compressors have a number of advantages over single-shaft. The design of such compressors gives opportunity to use an axial inlet for all stages and select the optimum rotational speed for each pair of impellers, which, along with the cooling of the gas after each stage, makes possible to achieve high levels of efficiency. The design of high-efficiency centrifugal compressor stages can be performed on the basis of highly effective stage elements. Such elements are: impellers with spatial blades, vaned and channel diffusers with given velocity distribution. In this paper, impellers with axial-radial blades are considered. The blade profile is determined by the specified pressure distribution along the blade. Such design improves the structure of the gas flow in the interblade channels of the impeller, which leads to an increase in its efficiency. Characteristics of loss coefficients from attack angles for impellers were obtained experimentally. Vaned and channel diffusers, the characteristics of which are given in this article, are designed with the given velocity distribution along the vane. Compared to the classic type of diffuser, such diffusers have lower losses and a wider range of economical operation. For diffusers as well as for impellers, characteristics of loss coefficients from attack angles were obtained. High efficient impellers and diffusers and obtained gas-dynamic characteristics were used in the design of a multi-shaft compressor unit for the production of liquefied natural gas. The initial pressure of the unit is 3bar. The obtained characteristics of loss coefficients from attack angles for the considered impellers and diffusers make it possible to calculate the gas-dynamic characteristics of high-efficient centrifugal compressors stages. The high-efficient centrifugal compressors stages can be designed using high-efficient elements, such as: impeller with spatial blades and vaned diffuser with given velocity distribution.
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Grzelczak, Mateusz. "The influence of efficiency of the cooling system on the thermodynamic parameters and performance of a two - stage VC 20.96 reciprocating compressor designed to serve as a marine engine starter." Polish Maritime Research 20, no. 4 (December 1, 2013): 25–33. http://dx.doi.org/10.2478/pomr-2013-0037.
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ABSTRACT The paper presents results of the research related to the analysis of the thermodynamic and flow processes occurring in a prototype VC 20.96 two-stage liquid-cooled reciprocating compressor. The compressor has been developed and manufactured by H. Cegielski Poznan metal works in collaboration with the Poznan University of Technology. The research related to the VC compressor was realized within the KBN 3127/C.T07-6/2002 project titled “Development of design of type-series of reciprocating compressors and their implementation in production”. The basic task of the project was to develop two type-series of liquid- and air- cooled reciprocating compressors of the V- and W- arrangement, designed to serve as marine engine starters. The result of the design work was the manufacturing of two compressors: the VC 20.96 liquid-cooled compressor and the WP 18.80 air-cooled one. The main aim of the research described in this paper was to evaluate the efficiency of the cooling system which uses inter-coolers integrated with the compressing stages and the cooperation of the compressing stages in terms of pressure ratio distribution. Owing to the cooling method, the applied design assumptions enabled to develop a compact compressor fulfilling the assumed operating parameters.
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Lu, Kui, Truong H. Phung, and Ibrahim A. Sultan. "On the Design of a Class of Rotary Compressors Using Bayesian Optimization." Machines 9, no. 10 (September 29, 2021): 219. http://dx.doi.org/10.3390/machines9100219.
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The optimization process of compressors is usually regarded as a ‘black-box’ problem, in which the mathematical form underlying the relationship between design parameters and the design objective is impractical and costly to be obtained. To solve the ‘black-box’ problem, Bayesian optimization has been proven as an accurate and efficient method. However, the application of such a method in the design of compressors is rarely discussed, particularly no work has been reported in terms of the positive displacement type compressor. Therefore, this paper aims to introduce the Bayesian optimization to the design of positive displacement compressors through the optimization process of the novel limaçon compressor. In this paper, a two-stage optimization process is presented, in which the first stage optimizes the geometric parameters as per design requirements and the second stage focuses on revealing an optimum setting of port geometries that improves machine performance. A numerical illustration is offered to prove the validity of the presented approach.
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Zhang, Tong, Chen Yang, Hu Wu, and Jinguang Li. "Quasi-2D Performance Analysis for Axial Compressors Based on Time-Marching Method." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 1 (February 2020): 114–20. http://dx.doi.org/10.1051/jnwpu/20203810114.
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In order to get a fast performance analysis tool for multi-stage axial compressors, a quasi-two dimensional analysis model based on time-marching method is developed in this paper. The model is based on Euler equation, and several source terms, like inviscid blade force model and viscous force model, are added to simulate different phenomena of compressor internal flow. The flow line in blade area is adjusted to solve the discontinuity problem at blade leading edge. Two test cases-PW3S1, a 3.5-stage axial compressor and a 1.5-stage high-speed axial compressor, are presented to validate the quasi-2D model. The overall performance characteristics of two compressors at different rotation speed are calculated then. The computed results are compared with experimental data or 3D results. The average errors of pressure ratio and efficiency are 0.52% and 0.63% in PW3S1 case, 1.73% and 2.91% in 1.5-stage compressor case, and the model is able to capture shock wave and to predict choke condition.
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Xu, Cheng, and Ryoichi S. Amano. "Empirical Design Considerations for Industrial Centrifugal Compressors." International Journal of Rotating Machinery 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/184061.
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Computational Fluid Dynamics (CFD) has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.
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Musgrave, D. S., and N. J. Plehn. "Mixed-Flow Compressor Stage Design and Test Results With a Pressure Ratio of 3:1." Journal of Turbomachinery 109, no. 4 (October 1, 1987): 513–19. http://dx.doi.org/10.1115/1.3262141.
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This paper presents a brief history of mixed-flow compressors, possible applications, and the design and measured performance of a recently tested 3:1 pressure-ratio stage. The stage is intended to run behind a multistage axial compressor; it has an envelope radius only 9.4 percent greater than the rotor tip radius. A tandem cascade diffusing system is used to promote flow range and thus aid matching to the axial stages. Compressor maps from the rig test are presented along with additional data (from static taps and exit rakes) that characterize the behavior of various elements of the stage.
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Gilge, Philipp, Andreas Kellersmann, Jens Friedrichs, and Jörg R. Seume. "Surface roughness of real operationally used compressor blade and blisk." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 14 (May 9, 2019): 5321–30. http://dx.doi.org/10.1177/0954410019843438.
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Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.
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Доценко, D. Dotsenko, Сторчеус, Yu Storcheus, Сторчеус, and M. Storcheus. "IMPROVING ENERGY EFFICIENCY OF TRANSPORT CARS BY OPTIMIZING CHARACTERISTICS OF THERMAL COMPRESSORS." Alternative energy sources in the transport-technological complex: problems and prospects of rational use of 3, no. 1 (March 16, 2016): 132–37. http://dx.doi.org/10.12737/18460.
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The features of the operating cycle and schematics thermal compressors operating on the principles of energy cascade. Factors affecting the efficiency of single- and two-stage thermal compressor circuits. The effect of operating and design parameters of the transformer cascade energy performance of one - and two-stage thermal compressor. Recommendations on further improvement of the thermal characteristics of the compressor cascade.
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Sdanghi, Giuseppe, Gaël Maranzana, Alain Celzard, and Vanessa Fierro. "Towards Non-Mechanical Hybrid Hydrogen Compression for Decentralized Hydrogen Facilities." Energies 13, no. 12 (June 17, 2020): 3145. http://dx.doi.org/10.3390/en13123145.
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The cost of the hydrogen value chain needs to be reduced to allow the widespread development of hydrogen applications. Mechanical compressors, widely used for compressing hydrogen to date, account for more than 50% of the CAPEX (capital expenditure) in a hydrogen refueling station. Moreover, mechanical compressors have several disadvantages, such as the presence of many moving parts, hydrogen embrittlement, and high consumption of energy. Non-mechanical hydrogen compressors have proven to be a valid alternative to mechanical compressors. Among these, electrochemical compressors allow isothermal, and therefore highly efficient, compression of hydrogen. On the other hand, adsorption-desorption compressors allow hydrogen to be compressed through cooling/heating cycles using highly microporous materials as hydrogen adsorbents. A non-mechanical hybrid hydrogen compressor, consisting of a first electrochemical stage followed by a second stage driven by adsorption-desorption of hydrogen on activated carbons, allows hydrogen to be produced at 70 MPa, a value currently required for the development of hydrogen automotive applications. This system has several advantages over mechanical compressors, such as the absence of moving parts and high compactness. Its use in decentralized hydrogen facilities, such as hydrogen refueling stations, can be considered.
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Shen, Hao, Zhaohua Li, Kun Liang, and Xinwen Chen. "Numerical modeling of a novel two-stage linear refrigeration compressor." International Journal of Low-Carbon Technologies 17 (2022): 436–45. http://dx.doi.org/10.1093/ijlct/ctac021.
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Abstract Linear compressors have started to apply in refrigeration owing to their oil-free operation, capacity modulation by variable stroke and higher seasonal efficiency. Nevertheless, linear compressors are subject to a high seal leakage loss and piston offset (drift), particularly at high pressure ratios. Meanwhile, there is a reduction in the accuracy of resonant frequency prediction due to very nonlinear gas spring at high pressure ratios, leading to a reduction in the compressor efficiency. Two-stage operation is considered as a feasible solution to the aforementioned issues due to the lower pressure ratio for each stage. A numerical model of two-stage compression system using linear compressors is presented in this study to investigate the system performance under various operating conditions. The proposed numerical model consists of a thermodynamic sub-model, a piston dynamic sub-model and a reed valve dynamic sub-model. Experiments are also conducted based on a refrigeration system with two linear compressors connected in parallel to validate the proposed model. The mean absolute percentage errors of the predicted mass flow rate and power input are 2.47% and 8.49%, respectively. The modeling results show that the coefficient of performance is 5.5 for a two-stage compression system and 2.0 for a single-stage compression system while the condenser temperature and evaporator temperature are 50°C and −23°C, respectively. The two-stage compression system offers superior performance to the single-stage system.
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Hsieh, W. H., and T. T. Wu. "Numerical Simulation and Experimental Investigation of Compression Processes of Two-Stage, very High Pressure Reciprocating Gas Compressors." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 208, no. 5 (September 1994): 287–98. http://dx.doi.org/10.1243/pime_proc_1994_208_131_02.
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To help the design of more reliable and efficient two-stage, very high pressure reciprocating gas compressors, a theoretical model and a numerical code for simulating compression processes in the compressors were developed and validated. The theoretical model considers time-dependent conservation equations of species, mass and energy, the equation of state, kinematic relationships and various convective heat-transfer correlations The theoretical model was solved numerically. Experimentally, a 207 MPa (30 000 lb/in2) very high pressure gas compressor was instrumented for measurements of various transient flow properties. The experimental data were analysed to achieve a better understanding of the compression processes of the compressor as well as for model validation. A parametric study was conducted with the theoretical model and numerical code to investigate the effect of various compressor parameters on the compressor performance. Among the parameters studied, it was found that the dead-end volume had the strongest effect on the performance of the compressor. A reduced dead-end volume would increase the volumetric efficiency and the maximum gas-phase temperature and pressure in the first-stage cylinder.
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Cruz-Manzo, Samuel, Senthil Krishnababu, Vili Panov, and Chris Bingham. "Inter-Stage Dynamic Performance of an Axial Compressor of a Twin-Shaft Industrial Gas Turbine." Machines 8, no. 4 (December 9, 2020): 83. http://dx.doi.org/10.3390/machines8040083.
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In this study, the inter-stage dynamic performance of a multistage axial compressor is simulated through a semi-empirical model constructed in the Matlab Simulink environment. A semi-empirical 1-D compressor model developed in a previous study has been integrated with a 0-D twin-shaft gas turbine model developed in the Simulink environment. Inter-stage performance data generated through a high-fidelity design tool and based on throughflow analysis are considered for the development of the inter-stage modeling framework. Inter-stage performance data comprise pressure ratio at various speeds with nominal variable stator guide vane (VGV) positions and with hypothetical offsets to them with respect to the gas generator speed (GGS). Compressor discharge pressure, fuel flow demand, GGS and power turbine speed measured during the operation of a twin-shaft industrial gas turbine are considered for the dynamic model validation. The dynamic performance of the axial-compressor, simulated by the developed modeling framework, is represented on the overall compressor map and individual stage characteristic maps. The effect of extracting air through the bleed port in the engine center-casing on transient performance represented on overall compressor map and stage performance maps is also presented. In addition, the dynamic performance of the axial-compressor with an offset in VGV position is represented on the overall compressor map and individual stage characteristic maps. The study couples the fundamental principles of axial compressors and a semi-empirical modeling architecture in a complementary manner. The developed modeling framework can provide a deeper understanding of the factors that affect the dynamic performance of axial compressors.
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Yusha, V. L., and S. S. Busarov. "Method for calculating actual capacity of single-stage long-stroke reciprocating compressors." Omsk Scientific Bulletin. Series Aviation-Rocket and Power Engineering 4, no. 4 (2020): 9–15. http://dx.doi.org/10.25206/2588-0373-2020-4-4-9-15.
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The article presents a generalized method for calculating the actual performance of low-speed longstroke air compressor stages of compression, based on determining the flow rate as a set of coefficients reflecting the influence of various factors on productivity losses. The method takes into account the design and operating features of low-speed long-stroke air compressor stages of compression and differs significantly from a similar method used to calculate high-speed stages of reciprocating compressors
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Künzelmann, M., R. Urban, R. Mailach, and K. Vogeler. "Active flow control at a 1.5-stage low-speed research compressor with varying rotor tip clearance." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 225, no. 7 (September 26, 2011): 886–96. http://dx.doi.org/10.1177/0957650911418150.
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The stable operating range of axial compressors is limited by the onset of rotating stall and surge. Mass injection upstream of the tip of an axial compressor rotor is a stability enhancement approach which can be effective in suppressing stall in tip-critical rotors, and thus increasing the operating range of compressors. In this article, investigations on active flow control related to the rotor tip gap sensitivity are discussed. The experiments were performed in a 1.5-stage low-speed research compressor. Measurements at part speed (80 per cent) and full speed (100 per cent) with varying injection rates are discussed. These tests were performed for two rotor tip clearances of 1.3 per cent and 4.3 per cent of rotor blade tip chord. Results on the compressor map, the flow field as well as transient measurements to identify the stall inception are discussed. Supplementary, the numerical results are compared to the experiments based on the configuration with the greatest benefit in operating range enhancement.
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Longley, J. P., and T. P. Hynes. "Stability of Flow Through Multistage Axial Compressors." Journal of Turbomachinery 112, no. 1 (January 1, 1990): 126–32. http://dx.doi.org/10.1115/1.2927409.
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This paper describes measurements of the performance of a research stage operating in isolation and as part of a multistage compressor. It is shown that the stall point and the stalled performance of the stage are properties of the system in which it operates rather than a property of the stage itself. The consequences of this for the estimation of the stall point for compressors and compression systems are discussed. The support that the measurements give to assumptions made by mathematical models which use the concept of an “underlying axisymmetric” characteristic, are highlighted.
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Wang, Gong Tao, Chen Zheng, and Abed Halimah. "Optimal Scheduling of Compressors Considering Linepack Storage in a Pipeline Network." Applied Mechanics and Materials 331 (July 2013): 271–76. http://dx.doi.org/10.4028/www.scientific.net/amm.331.271.
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This paper presents an algorithm using dynamic programming to solve the problem of opitimal scheduling of compressors considering the linepack storage in a pipeline network. Both centrifugal and piston compressors are modelled for power calculation. For a forecast profile of gas loads, a multi-stage problem is formed by discretizing the storage capacity of linepack and tank along the timeline, and then is solved by a dynamic programming to obtain optimal day-ahead schedules for each compressor. While creating the multi-stage data, constraints on compressors, stations (sources), and pipeline network are utilized to exclude infeasible paths, avoiding dimension disaster and ensuring the feasibility of the paths from the point of view of state transition. Case studies have been done on both simple and complex systems, and the results indicate the practicability of the proposed algorithm.
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Dalbert, P., M. V. Casey, and E. Schurter. "Development, Testing, and Performance Prediction of Radial Compressor Stages for Multistage Industrial Compressors." Journal of Turbomachinery 110, no. 3 (July 1, 1988): 283–92. http://dx.doi.org/10.1115/1.3262194.
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A review of some theoretical and experimental techniques currently in use for the aerodynamic development of standard stages for industrial centrifugal compressors is presented. Design methods for standardized families of radial compressor stages are summarized. The closed-loop test stands used for performance measurements are described and methods of test data analysis for identifying component performance and improving component matching are discussed. Test data obtained from standardized families of stages are analyzed using elementary dimensional analysis. This allows a simple structure for the interpolation of the large amounts of test data to be formulated. Correction formulae for secondary effects (such as changes in gas properties, Reynolds number, and small deviations from geometric similarity) are also derived from measurements. The data are incorporated into a stage-stacking calculation method for performance prediction of multistage compressors.
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Day, I. J., and C. Freeman. "The Unstable Behavior of Low and High-Speed Compressors." Journal of Turbomachinery 116, no. 2 (April 1, 1994): 194–201. http://dx.doi.org/10.1115/1.2928353.
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By far the greater part of our understanding about stall and surge in axial compressors comes from work on low-speed laboratory machines. As a general rule, these machines do not model the compressibility effects present in high-speed compressors and therefore doubt has always existed about the application of low-speed results to high-speed machines. In recent years interest in active control has led to a number of studies of compressor stability in engine-type compressors. The instrumentation used in these experiments has been sufficiently detailed that, for the first time, adequate data are available to make direct comparisons between high-speed and low-speed compressors. This paper presents new data from an eight-stage fixed geometry engine compressor and compares them with low-speed laboratory data. The results show remarkable similarities in both the stalling and surging behavior of the two machines, particularly when the engine compressor is run at intermediate speeds. The engine results also show that, as in the laboratory tests, surge is precipitated by the onset of rotating stall. This is true even at very high speeds where it had previously been thought that surge might be the result of a blast wave moving through the compressor. This paper therefore contains new information about high-speed compressors and confirms that low-speed testing is an effective means of obtaining insight into the behavior of high-speed machines.
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Kalinkevych, Mykola, and Andriy Skoryk. "Design Method for Channel Diffusers of Centrifugal Compressors." International Journal of Rotating Machinery 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/589357.
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The design method for channel diffusers of centrifugal compressors, which is based on the solving of the inverse problem of gas dynamics, is presented in the paper. The concept of the design is to provide high pressure recovery of the diffuser by assuming the preseparation condition of the boundary layer along one of the channel surfaces. The channel diffuser was designed with the use of developed method to replace the vaned diffuser of the centrifugal compressor model stage. The numerical simulation of the diffusers was implemented by means of CFD software. Obtained gas dynamic characteristics of the designed diffuser were compared to the base vaned diffuser of the compressor stage.
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Simon, H., T. Wallmann, and T. Mo¨nk. "Improvements in Performance Characteristics of Single-Stage and Multistage Centrifugal Compressors by Simultaneous Adjustments of Inlet Guide Vanes and Diffuser Vanes." Journal of Turbomachinery 109, no. 1 (January 1, 1987): 41–47. http://dx.doi.org/10.1115/1.3262068.
Full textAbstract:
Nowadays, multistage geared centrifugal compressors are most often equipped with three-dimensional impellers and adjustable inlet guide vane cascades, at least upstream of the first stage. Optimum stage efficiencies are made possible by optimum axial in-flow into each stage and freely selectable pinion shaft speeds. Combined with intercooling of the medium, the result is high machine efficiency with good operating ranges. Additional increases in efficiency can be achieved by means of vaned diffusers. Due to the attendant restriction to the working range, this solution is not common in production compressors. Nevertheless, the working range can be distinctly expanded by adjusting the diffuser vanes. In addition, the combination of simultaneous adjustment to inlet guide vanes and diffuser vanes enables an increase in machine efficiency over the entire operating range as compared with regulation using only inlet guide vanes or diffuser vanes. This paper reports on the development of centrifugal compressor stages equipped with vaned diffusers. The impellers have backward-curved blades. Experimental determination of suitable schedules for simultaneous adjustment of both inlet guide vanes and diffuser vanes, depending on the desired performance characteristic, will be dealt with in detail. Furthermore, some examples of the overall performance maps for multistage inter-cooled geared compressors will be shown as a result of combining the performance characteristic curves of the individual stages. The operating ranges and regions of maximum efficiency are optimally matched to the requirements in question by means of suitable adjustment schedules.
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Simonov, Nikolay, Igor Krivosheev, and Kirill Rozhkov. "SELECTION AND OPTIMIZATION OF THE MAIN PARAMETERS OF TURBOCOMPRESSORS IN THE DESIGN AND FINE-TUNING OF GAS TURBINE ENGINES." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 67 (2021): 96–106. http://dx.doi.org/10.15593/2224-9982/2021.67.09.
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The choice and optimization of the rotational speed, the number of stages, the axial velocities distribution, reactivity, diametric dimensions and flow path shape, the blade rows width, changes in the height of the flow path in the compressors and turbines of the gas turbine engine are considered. The method for determining the total pressure recovery ratio and its relationship with the efficiency of blade rows, stages, compressors and turbines is proposed. It is shown that with the same value of this indicator in these elements, the maximum efficiency of compressors and turbines in the composition of turbocompressors is achieved. It is proposed to use this indicator at an early design stage to determine the optimal stages number and the work distribution between them, the change in work along the flow path height. It is shown how the position of the points for the stages and the optimal flow path shape are determined on the Smith diagrams. Various methods are proposed for parameters choosing of the blade profiles for the first, last and for intermediate steps. It is shown how these methods are used when fine-tuning compressors and turbines based on the results of GTE tests. The results of approbation of the developed design and refinement methods are given on examples of changing the geometry of the blade rows and the flow path in the replaceable flow path of the centrifugal blower for the R-16 "Ufa" gas compressor unit, the refinement of the 3-stage LPC for perspective two spool turbofan engine, comparison with the results of simulation in the DVIGw system , 2D and 3D CAD / CAE-modeling.
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B. Jadhav, Sachin, Jayamala K. Patil, and Ramesh T. Patil. "Design and Implementation of Modified Partial Product Reduction Tree for High Speed Multiplication." International Journal of Reconfigurable and Embedded Systems (IJRES) 2, no. 1 (March 1, 2013): 15. http://dx.doi.org/10.11591/ijres.v2.i1.pp15-20.
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This paper presents the details of hardware implementation of modified partial product reduction tree using 4:2 and 5:2 compressors. Speed of multiplication operation is improved by using higher compressors .In order to improve the speed of the multiplication process within the computational unit; there is a major bottleneck that is needed to be considered that is the partial products reduction network which is used in the multiplication block. For implementation of this stage require addition of large operands that involve long paths for carry propagation. The proposed architecture is based on binary tree constructed using modified 4:2 and 5:2 compressor circuits. Increasing the speed of operation is achieved by using higher modified compressors in critical path. Our objective of work is, to increase the speed of multiplication operation by minimizing the number of combinational gates using higher n:2 compressors. The experimental test of the proposed modified compressor is done using Spartan-3FPGA device (XC3S400 PQ-208). Using tree architectures for the partial products reduction network represent an attractive solution that is frequently applied to speed up the multiplication process. The simulation result shows 4:2 and 5:2 compressor output which is done using Questa Sim 6.4c Mentor Graphics tool.
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Tan, J., X. Wang, D. Qi, and R. Wang. "The effects of radial inlet with splitters on the performance of variable inlet guide vanes in a centrifugal compressor stage." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 9 (June 28, 2011): 2089–105. http://dx.doi.org/10.1177/0954406211407799.
Full textAbstract:
Variable inlet guide vanes (VIGVs) can regulate pressure ratio and mass flow at constant rotational speed in centrifugal compressors as a result of inducing a controlled prewhirl in front of impellers. Radial inlets and VIGVs are typical upstream components in front of the first-stage impellers in many industrial centrifugal compressors. However, previous investigations on VIGVs in centrifugal compressors were mostly conducted under the condition of axial inlets, and this study aims to focus on the effects of radial inlet on the VIGVs performance of a centrifugal compressor stage. The axial inlet stage model is compared with the radial inlet stage model with splitters using numerical flow simulation. The flow from the radial inlet was non-uniform in both circumferential and radial directions; thus, the VIGVs, the impeller, the vaneless diffuser, and the return vane channel are modelled with fully 360° passages. The three-dimensional (3D) flow field is numerically simulated at VIGVs setting angles ranging from - 20° to 60°. The overall stage performance parameters are obtained by integrating the field quantities. Though the splitters are equipped in the radial inlet, the overall stage polytropic efficiency decreases by an average of 4 per cent and total pressure ratio decreases by an average of 3.3per cent in comparison with the axial stage model. This can be attributed to the effect of both flow non-uniformity induced by radial inlet and flow loss in the radial inlet at different VIGV setting angles. The flow loss in the radial inlet with splitters is the main reason of the stage performance decrease compared with the flow non-uniformity. The simulation results show that the performance of VIGVs is degraded by its inlet flow distortions resulting from a radial inlet. The results in this study can be applied to centrifugal compressor design and optimization.
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Hall, E. J. "Aerodynamic modelling of multistage compressor flow fields Part 1: Analysis of rotor-stator-rotor aerodynamic interaction." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 212, no. 2 (February 1, 1998): 77–89. http://dx.doi.org/10.1243/0954410981532153.
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The primary purpose of this study was to investigate improved numerical techniques for predicting flows through multistage compressors. The vehicle chosen for this study was the Pennsylvania State University Research Compressor (PSRC). The PSRC facility consists of a 3 1/2-stage axial flow compressor which shares design features which are consistent with embedded stages of modern gas turbine engine axial flow compressors. In Part 1 of this two-part paper, several computational fluid dynamics techniques were applied to predict both steady and unsteady flows through the PSRC facility. Interblade row coupling via a circumferentially averaged mixing-plane approach was employed for steady flow analysis. A mesh density sensitivity study was performed to define the minimum mesh requirements necessary to achieve reasonable agreement with the experimental data. Time-dependent flow predictions were performed using a time-dependent interblade row coupling technique. These calculations evaluated the aerodynamic interactions occurring between rotor 2, stator 2 and rotor 3 for the PSRC rig.
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Ho¨nen, H., and H. E. Gallus. "Monitoring of Aerodynamic Load and Detection of Stall in Multistage Axial Compressors." Journal of Turbomachinery 117, no. 1 (January 1, 1995): 81–86. http://dx.doi.org/10.1115/1.2835645.
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The unsteady flow in a single-stage axial flow compressor at different operating conditions has been investigated with hot-wire and hot-film probes to find out the influence of the aerodynamic compressor load on the periodic fluctuations. These results are compared with measurements in the last stages of a multistage high-pressure compressor of a gas turbine for normal operation and under stall conditions. From the patterns of the frequency spectra of the measuring signals a parameter for the detection of the approach to the stability line of a compressor is derived. A method for the on-line monitoring of the aerodynamic load is presented. Based on these results a monitoring system has been developed. First experiences with this system, applied to two multistage compressors, are reported.
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Cicciotti, Matteo, Dionysios P. Xenos, Ala EF Bouaswaig, Nina F. Thornhill, and Ricardo F. Martinez-Botas. "Physical modelling of industrial multistage centrifugal compressors for monitoring and simulation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 18 (March 24, 2015): 3433–48. http://dx.doi.org/10.1177/0954406215572433.
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Currently, industrial applications to monitoring, simulation and optimization of compressors employ empirical models that are either data-driven or based on the manufacturer performance maps. This paper proposes the use of one-dimensional aerodynamic models for industrial applications such as simulation and monitoring. The physical model establishes causality relationships among input and output variables that are tuned to match the real compressor by using operation data. The application of the method is shown using data from an industrial multistage centrifugal compressor with interstage coolers and variable inlet guide vanes. This is a more complex but more relevant case study for process industry, as opposed to the single-stage variable speed compressors, which is the common example in the literature.
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Auchoybur, Kiran, and Robert Miller. "The sensitivity of 3D separations in multi-stage compressors." Journal of the Global Power and Propulsion Society 2 (February 26, 2018): 34C05T. http://dx.doi.org/10.22261/jgpps.34c05t.
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Abstract One of the most important questions facing a compressor designer is how accurately their computational code predicts the size of 3D corner separations. This is because the size of the 3D corner separation sets the compressors off-design performance and blockage and therefore it’s operating range. The aim of this paper is to determine how two types of modelling fidelities limit the accuracy of the prediction of 3D corner separations. The first modelling fidelity is the accuracy with which the flow within a blade passage is modelled (endwall geometry modelling, shroud modelling and the boundary layer transition modelling). The second modelling fidelity is the accuracy of modelling in the multi-blade row environment (multi-stage repeating stage boundary layer modelling and the local skew endwall boundary layer modelling). The first part of the paper shows that when the compressor studied has its original “design intent” geometry (defined as 1% shroud clearance and a hydraulically smooth blade surface) the size of the 3D corner separation is relatively insensitive to the modelling fidelities within the blade row but is highly sensitive to modelling fidelity in the multi-blade row environment. This explains the inability of 3D CFD to predict multistage matching. The second part of the paper shows that when the compressor has its “end of life” geometry (defined as 3% shroud clearance and surface roughness measured from an engine blade at 4,000 cycles) the size of the 3D corner separation suddenly becomes highly sensitivity to modelling fidelities within an individual blade row. This finding is of significant importance to designers because it shows that current computational codes are not able to predict end of life performance.
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Koyyalamudi, V. V. N. K. Satish, and Quamber H. Nagpurwala. "Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment." International Journal of Rotating Machinery 2016 (2016): 1–19. http://dx.doi.org/10.1155/2016/2371524.
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The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment) was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.
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Zhu, Yu Feng. "Development of Reciprocating Air-Cool Oilless Compressors Series Product." Advanced Materials Research 201-203 (February 2011): 1429–32. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.1429.
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Research and development are made about reciprocating air-cool oilless compressors series products in order to meet maket demond. Piston pings and guiding pings are made by filled PTFE material to achieve the oilless lubrication between cylinders and pistons. Grease lubrication bearings are used and designed in structure to achieve the oilless lubrication of connecting rod larger heads, connecting rod smaller heads and main bearings. The optimal dynamic balance can achieve by a new-type dynamic balance system which are made up of inner balance weight and outer balance weight to make the compressor run stationary. The crankcase bottom are all opened, three-stage fans are used to cool the compressor, these make the compressor cool better to improve the compressor life. The radius-length ratio λ is taken as 1/6 to 1/7 to reduce side pressure greatly. The reciprocating air-cool oilless compressors series products have better properties, can run smoothly and reliably and go into mass production.
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Garnier, V. H., A. H. Epstein, and E. M. Greitzer. "Rotating Waves as a Stall inception Indication in Axial Compressors." Journal of Turbomachinery 113, no. 2 (April 1, 1991): 290–301. http://dx.doi.org/10.1115/1.2929105.
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Stall inception has been studied in two low-speed compressors (a single-stage and a three-stage) and in a high-speed three-stage compressor, using temporally and spatially resolved measurements. In all three machines, rotating stall was preceded by a period in which small-amplitude waves were observed traveling around the circumference of the machine at a speed slightly less than the fully developed rotating stall cell speed. The waves evolved smoothly into rotating stall without sharp changes in phase or amplitude, implying that, in the machines tested, the prestall waves and the fully developed rotating stall are two stages of the same phenomenon. The growth rate of these disturbances was in accord with that predicted by current analytical models. The prestall waves were observed both with uniform and with distorted inflow, but were most readily discerned with uniform inflow. Engineering uses and limitations of these waves are discussed.
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Ferdaus, F., Nitish Kumar, G. Sakthivel, and N. Raghukiran. "Stage reduced counter-rotating axial compressor for jet engine." International Journal for Simulation and Multidisciplinary Design Optimization 12 (2021): 3. http://dx.doi.org/10.1051/smdo/2021006.
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Variation in the states of system, mass flow and pressure are some of the disturbances which are experienced by the compressors in the jet engine under working condition. One of the main factors that influence the efficiency of a jet engine is the pressure ratio. In order to achieve the required pressure ratio, we should have relatively a greater number of stages in the compressor that leads to an increase in the weight of the engine. The stator and rotor are the essential parts of an aircraft's axial compressor. CFD is used in order to evaluate the pressure ratio. In this paper, we are going to analyze a three-stage compressor instead of an actual six-stage compressor. The mass flow rate inside the control system can be used to maintain the stability of the system. Compressor weight and pressure ratio at each stage can be reduced if we have a clockwise and anti-clockwise rotating rotor. With the use of a universal gear system, the two clockwise rotors and one anti-clockwise rotor were analyzed. The main outlook of this work is to show the maximum pressure ratio of the compressor at the outlet with our desired configurations. In conclusion, it was shown that the weight of the aircraft engine can be effectively reduced.
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Wang, Yu, and Zhen Luo. "CFD Modeling of Flow Performance inside Subsonic Centrifugal Compressor." Advanced Materials Research 291-294 (July 2011): 251–54. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.251.
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Centrifugal Compressors, which offer good flow stability, compact size and high stage pressure ratio, have been widely used in helicopter engines and sometime served as high pressure stage in small turbojet engines. In this paper, a method of developing a CFD model is presented for investigating the flow performance of a subsonic centrifugal compressor. The configuration used for the study is a subsonic centrifugal compressor which has a 60mm diameter impeller. A CFD modeling is carried out to obtain the performance and operational range of the compressor stage. The mesh independence studies were performed to provide confidence in the numerical results at operation speed. Particular emphasis is laid on the flow performance analysis with designed rotational speed of impeller.
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Yablokov, Aleksey, Ivan Yanin, Aleksey Danilishin, and Anatoliy Zuev. "Ansys CFX numerical study of stages centrifugal compressor with low-flow rate coefficient." MATEC Web of Conferences 245 (2018): 09002. http://dx.doi.org/10.1051/matecconf/201824509002.
Full textAbstract:
The article presents results of applying the methods of computational fluid dynamics for model low-flow rate stages of centrifugal compressors with flow rate coefficient F = 0.028. The computational domain of a model centrifugal compressor for CFD-simulation consists of the following elements: inlet chamber, impeller, vaneless diffuser, return channel, outlet chamber, shaft seal labyrinth, front and back shroud leakage. Full-scale experimental studies were conducted to model stage 028 in air at an inlet pressure of p* = 1 atm. Numerical research for stage 028 held with flow rate coefficient F=(0.019-0.046) for three variants trailing edge of the impeller. According to the results of numerical research are constructed performances of stages centrifugal compressor and conducted verification of results. Estimated discrepancy between the results of numerical researches on the model with shaft seal labyrinth and without shaft seal labyrinth.
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Tarabrin, A. P., V. A. Schurovsky, A. I. Bodrov, and J. P. Stalder. "An Analysis of Axial Compressor Fouling and a Blade Cleaning Method." Journal of Turbomachinery 120, no. 2 (April 1, 1998): 256–61. http://dx.doi.org/10.1115/1.2841400.
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The paper describes the phenomenon of axial compressor fouling due to aerosols contained in the air. Key parameters having effect on the level of fouling are determined. A mathematical model of a progressive compressor fouling using the stage-by-stage calculation method is developed. Calculation results on the influence of fouling on the compressor performance are presented. A new index of sensitivity of axial compressors to fouling is suggested. The paper gives information about Turbotect’s deposit cleaning method of compressor blading and the results of its application on an operating industrial gas turbine. Regular on-line and off-line washings of the compressor flow path make it possible to maintain a high level of engine efficiency and output.
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Amin Mobarak, Mostafa Shawky Abdel Moez, and Shady Ali. "Quasi Three-Dimensional Design for a Novel Turbo-Vapor Compressor and the Last Stage of a Low-Pressure Steam Turbine." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 85, no. 2 (August 5, 2021): 1–13. http://dx.doi.org/10.37934/arfmts.85.2.113.
Full textAbstract:
Turbo-vapor compressors (TVCs) are used to create a vacuum pressure in the evaporator of a novel combined cycle for electricity and freshwater production invented by Amin Mobarak. A novel design conceived of a TVC is introduced to increase the efficiency, allowable mass flow rate and reduce costs and losses. The system consists of a single axial compressor rotor followed by a single axial turbine rotor, which drives the upstream compressor, allowing high flow rates. A quasi-3D design is carried out for the TVC to calculate the flow velocity components and angles and ensure that the turbo-vapor turbine work is equal to the turbo-vapor compressor work. A preliminary design of the low-pressure power turbine (LPT) is done to examine the size and number of stages. The (LPT) size is twice the size of TVC at typical cycle operating conditions. A three-stage design is the most appropriate choice for the number of stages. It satisfies the accelerating relative flow condition at the last stage over a range of flow coefficients. A quasi-3D design is carried out for the LPT's last stage to ensure a multi-stage power turbine's safe design.
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Zhao, Wenfeng, Qun Zheng, Bin Jiang, and Aqiang Lin. "A Passive Control Method of Hub Corner Stall in a 1.5-Stage Axial Compressor under Low-Speed Conditions." Energies 13, no. 11 (May 27, 2020): 2691. http://dx.doi.org/10.3390/en13112691.
Full textAbstract:
Since the use of the compressor of a ship gas turbine is unavoidable at a low-speed operation, the flow field characteristics and stall mechanism at off-design speeds are important aspects for compressor designers. In this study, the first 1.5 stages of an eight-stage compressor are numerically simulated. The mechanism of compressor rotor instability at lower speeds is identified. The characteristic lines of compressors with various partial clearance are calculated at low speed (0.6 N). The flow field of the same outlet pressure (near stall point of the original compressor without clearance) is compared and analyzed. The results show that, at the near stall point, the suction surface separation and backflow occur in the main flow of the rotor top. It develops along the blade span and finally blocks the flow passage of the rotor, which results in the compressor stall. At the same time, the stall also occurs at the corner of the stator hub. In this paper, the characteristics of partial clearance in four different positions of the stator hub are analyzed. The near stall point and the working point are selected for the flow field analysis. It is concluded that the radial development of the stall vortex on the suction surface of the stator can be restrained by the partial clearance at the stator. In this paper, a passive control method by partial clearance is used in the real compressors, which is different from previous studies on cascades. The margin increases at low speeds.