Статті в журналах з теми "Annular groove"
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1
Thawornsathit, Phongsakorn, Ekachai Juntasaro, Hwanjit Rattanasonti, Putapon Pengpad, Karoon Saejok, Chana Leepattarapongpan, Ekalak Chaowicharat, and Wutthinan Jeamsaksiri. "Enhancing Performance of a MEMS-Based Piezoresistive Pressure Sensor by Groove: Investigation of Groove Design Using Finite Element Method." Micromachines 13, no. 12 (December 17, 2022): 2247. http://dx.doi.org/10.3390/mi13122247.
Анотація:
The optimal groove design of a MEMS piezoresistive pressure sensor for ultra-low pressure measurement is proposed in this work. Two designs of the local groove and one design of the annular groove are investigated. The sensitivity and linearity of the sensor are investigated due to the variations of two dimensionless geometric parameters of these grooves. The finite element method is used to determine the stress and deflection of the diaphragm in order to find the sensor performances. The sensor performances can be enhanced by creating the annular or local groove on the diaphragm with the optimal dimensionless groove depth and length. In contrast, the performances are diminished when the local groove is created on the beam at the piezoresistor. The sensitivity can be increased by increasing the dimensionless groove length and depth. However, to maintain low nonlinearity error, the annular and local grooves should be created on the top of the diaphragm. With the optimal designs of annular and local grooves, the net volume of the annular groove is four times greater than that of the local groove. Finally, the functional forms of the stress and deflection of the diaphragm are constructed for both annular and local groove cases.
2
Robrecht, Robin M., and Peter F. Pelz. "Lubrication Film Friction Model for Grooved Annular Seals." International Journal of Turbomachinery, Propulsion and Power 8, no. 4 (November 10, 2023): 45. http://dx.doi.org/10.3390/ijtpp8040045.
Анотація:
Grooved liquid annular seals have a significant influence on the design of turbomachines. Corresponding lubrication film models need to account for the different friction behavior of the grooves compared to plain seals. However, there is a lack of reliable and validated models for this purpose. Thus, the applicability of a friction factor model is explored and a calibration method is presented. A single square groove is investigated by means of 96 steady-state RANS simulations for different operation conditions and groove geometries. The results are used to calibrate the friction model and successfully verify it in terms of the pressure drop over the groove. For validation, two full grooved seals with relatively large square grooves were investigated by experiment. The friction model was incorporated in a lubrication model and compared to the measurement data for the pressure difference and the resulting force for specified leakage and eccentricity. The model predictions for the pressure difference can be considered very good. The force predictions show significant deviation, but can be considered acceptable given the low force magnitudes and measurement uncertainty. The results offer a general validity to our friction model approach, assumptions and the calibration method.
3
Yifang, Sun, O. G. Grebenikov та O. O. Vendin. "ВПЛИВ КІЛЬЦЕВИХ КАНАВОК ХОЛОДНОГО ОБТИСКУ НА ДОВГОВІЧНІСТЬ ПАНЕЛЕЙ КРИЛА З ФУНКЦІОНАЛЬНИМИ ОТВОРАМИ". Open Information and Computer Integrated Technologies, № 99 (24 червня 2024): 22–31. http://dx.doi.org/10.32620/oikit.2023.99.02.
Анотація:
This article studies in detail the method of cold extrusion annular grooves to solve the problem of aircraft fatigue life extension that reduces the fatigue life of aircraft wing panels due to functional holes. This method is a very simple and effective anti-fatigue manufacturing technology. In order to simulate the different wing panels with functional holes, the experiment is designed to extrude the specimen with different extrusion forces to obtain annular grooves of different depths. Fatigue tests are conducted on specimens with annular grooves. The test results show that: 1) Cold extrusion annular grooves can extend the fatigue life of wing panels with functional holes; 2) The fatigue life of wing panels with functional holes is affected by the depth of the cold extrusion annular groove. The fatigue life changes in an inverted "V" shape as the depth of the cold extrusion annular groove increases; 3) When cold extrusion annular groove depth is 0.26mm, the fatigue life of specimen with holes is maximum, and the fatigue life is increased by 2.35~32.9 times when specimen thickness is 5 mm
4
Childs, Dara W., Luis E. Rodriguez, Vito Cullotta, Adnan Al-Ghasem, and Matthew Graviss. "Rotordynamic-Coefficients and Static (Equilibrium Loci and Leakage) Characteristics for Short, Laminar-flow Annular Seals." Journal of Tribology 128, no. 2 (September 28, 2005): 378–87. http://dx.doi.org/10.1115/1.2164468.
Анотація:
Test results are presented for laminar-flow seals that are representative of buffered-flow oil seals in centrifugal compressors. The seals are short (L∕D≅0.21), with a diameter of 117mm and a clearance-to-radius ratio 0.0007. A smooth seal, a seal with one central groove, and a seal with three grooves were tested. Groove geometries employed are representative of industrial practice for compressors with a groove-depth to clearance ratio on the order of 6. Tests were conducted at 4000, 7000, and 10,000rpm shaft speed with delta pressures across the seals of 21, 45, and 69bars. For all cases, the flow was laminar. The seals were tested from a centered position out to an eccentricity ratio of 0.7. Static data included leakage and equilibrium loci for a range of loads. Direct and cross-coupled stiffness and damping coefficients and direct mass coefficients were determined from dynamic tests. For the smooth seal, comparisons between measurements and predictions were reasonable for the direct and cross-coupled stiffness and damping coefficients; however, measured added mass coefficients were roughly ten times larger than predicted. Predictions for the grooved seals from a “deep-groove” model that assumed zero pressure oscillations in the grooves greatly over predicted the influence of the grooves. In a centered position, smooth and grooved seals had comparable leakage performance. At higher eccentricity ratios, the grooved seals leaked modestly more. For eccentricity ratios less than approximately 0.3, the grooved seals and the smooth seal had qualitatively similar static and dynamic characteristics. In terms of cross-coupled stiffness coefficients, the grooved seals were less stable than the smooth seal at eccentricity ratios greater than approximately 0.5 but had significantly lower cross-coupled coefficients at reduced eccentricity ratios between zero and 0.3. A grooved centered seal is more stable than a smooth centered seal. The smooth seal had higher damping than the grooved seals and had moderately better centering capabilities.
5
Yen, S. C., and C. L. Shih. "Improving Combustion Intensity and Modulating Flame Behaviors Using Helical-Grooved Cones." Journal of Mechanics 29, no. 2 (December 20, 2012): 273–80. http://dx.doi.org/10.1017/jmech.2012.134.
Анотація:
AbstractFour helical-grooved cones were installed behind an unconfined combustion nozzle to increase the bluff-body effect and turbulence intensity (T.I.). The cone configurations included a smooth cone and the other three cones cut with 1, 2 and 3 helical v-grooves. Experimental results showed that the helical v-grooves transformed the axial momentum (or the axial velocity) to the angular momentum (or the angular velocity). TheT.I.was enhanced by increasing the tangential component of fuel-jet momentum. The direct photography and thermocouple were utilized to observe the flame structures and to delineate the characteristic flame modes, flame length, temperature distribution, and combustion intensity. The flame modes were classified as jet flame, flickering flame, bubble flame, recirculation flame, lifted flame and ring flame. The flame length decreases as the groove number increases. The increasedT.I.and groove number (or bluff-body effect) improve the fuel-air mixing. The total combustion intensity increases with annular-air jet and with the groove number.
6
Редин, И. И., та М. А. Шевченко. "УЛУЧШЕНИЕ ТОПЛИВНОЙ ЭФФЕКТИВНОСТИ ГАЗОТУРБИННОГО ДВИГАТЕЛЯ УСТАНОВКОЙ В КОМПРЕССОРЕ НАДРОТОРНОГО УСТРОЙСТВА". Open Information and Computer Integrated Technologies, № 81 (16 листопада 2018): 72–85. http://dx.doi.org/10.32620/oikit.2018.81.08.
Анотація:
The analysis of the influence of annular grooves on the flow in the compressor rotor air gas channel and the axial compressor characteristics as well as on the fuel efficiency of the gas turbine engine is presented. The hypothetical mechanism of the flow effect in the cavity of the annular groove on the main flow in the tip end of the blade air-foil of the axial compressor stage is outlined. The effectiveness of the casing treatment in the form of single annular groove, width is 20% of the axial projection of the chord of the tip end section of the blade is shown experimentally in a single-stage and multi-stage axial compressor system. The increase of the compressor efficiency with ten single annular grooves installed above the leading edges of the blades of each stage, has reduced the specific fuel consumption of the serial GTE in its main operating modes.
7
Razzzaque, M. Mahbubur, and Takahisa Kato. "Effects of a Groove on the Behavior of a Squeeze Film Between a Grooved and a Plain Rotating Annular Disk." Journal of Tribology 121, no. 4 (October 1, 1999): 808–15. http://dx.doi.org/10.1115/1.2834139.
Анотація:
A model simulating the squeezing process of an annular disk rotating against a grooved counterpart has been developed. Grooving effects are incorporated using the narrow groove assumption. Disks are considered impermeable, rigid, perfectly aligned, and smooth. It is assumed that the fluid film is isothermal and obeys Reynolds equation. The governing equations derived from the model are solved numerically. The effects of groove geometry, orientation and applied load on film thickness, transmitted torque, speed, squeeze time, and viscous power dissipation have been calculated and analyzed. It has been found that angular orientation significantly affects the squeezing process. Squeeze time and power dissipation are less for grooves with angular orientation in the range 40–60 deg.
8
Childs, Dara W., Matthew Graviss, and Luis E. Rodriguez. "Influence of Groove Size on the Static and Rotordynamic Characteristics of Short, Laminar-Flow Annular Seals." Journal of Tribology 129, no. 2 (January 5, 2007): 398–406. http://dx.doi.org/10.1115/1.2647471.
Анотація:
Test results are presented for a smooth seal and three centrally grooved seals that are representative of buffered-flow oil seals in centrifugal compressors. The seals are short (L∕D≅0.21), with a diameter of 117mm and a nominal radial clearance of 0.085mm, netting the clearance-to-radius ratio 0.0015. The grooves have groove depth to clearance ratios (Dg∕Cr) of 5, 10, and 15. Test conditions include three shaft speeds from 4000rpm to 10,000rpm, three inlet oil pressures from 24bar to 70bar, and seal eccentricity ratios from 0 (centered) to 0.7. Dynamic results include stiffness, damping, and added-mass coefficients; static results include stator position, attitude angles, and seal leakage. Stiffness, damping, and mass coefficients plus leakage are compared for the seal geometries. Results show that all rotordynamic coefficients consistently decrease with increasing seal groove depths, and seal leakage is largely unchanged. Comparisons are also made between experimental results and predictions from a computer program based on a Reynolds + energy equation model. The model includes the assumption that a groove is large enough to create separate lands within the seal, creating a zero or negligible pressure perturbation within the groove. Test results show that even the deepest groove depth tested is not deep enough to satisfy this assumption.
9
Lin, Zhimin, Ruixia Yang, Haihong Yang, Liangbi Wang, Yongheng Zhang, and Anning Guo. "Parametric effect of the interrupted annular groove fin on flow and heat transfer characteristics of a finned circular tube heat exchanger." Thermal Science, no. 00 (2022): 40. http://dx.doi.org/10.2298/tsci211015040l.
Анотація:
The influences of the geometrical parameters of interrupted annular groove fin (IAGF) mainly including the annular groove diameter, the groove arc length, and the fin spacing, on the fin side thermal-hydraulic characteristics of a finned circular tube exchanger were numerically investigated by actualizing the custom FORTRAN programing with SIMPLE algorithm in a nonorthogonal curvilinear coordinate system, and the regression formulas of average Nusselt number and friction factor with flow parameters and geometrical parameters were obtained. Compared with the referential plain fin, IAGF could significantly improve thermal performance under the same pumping power constraint, and Nusselt number is closely germane to the secondary flow, which implies that the fin side heat transfer is depended entirely on the secondary flow strength. For Nusselt number, the annular groove diameter and the groove arc length have positive effect, while the fin pitch, the groove circumferential and radial locations have negative effect. The dominant parameters influencing on friction factor in turn are the fin pitch, the groove radial location, and the annular groove diameter. The optimal annular groove diameter is screened, and found that the optimal annular groove diameter is closely related with Reynolds number under the same pumping power constraint, while under the same mass flow rate constraint that is scarcely related with Reynolds number.
10
Childs, D. W., S. A. Nolan, and J. J. Kilgore. "Test Results for Turbulent Annular Seals, Using Smooth Rotors and Helically Grooved Stators." Journal of Tribology 112, no. 2 (April 1, 1990): 254–58. http://dx.doi.org/10.1115/1.2920250.
Анотація:
Test results, consisting of leakage data, friction factors, and rotordynamic force coefficients, are presented for seven annular seals using smooth rotors and helically-grooved stators. All seals have the same nominal clearances and groove depths. The helix angles vary from zero (circumferential grooving) to 70 deg. The number of grooves and the leakage rates increase steadily with increasing helix angles. Helically-grooved stators leak more than smooth seals for helix angles greater than 30 deg. The effective direct stiffness of the seals first decreases and then increases with increasing helix angles. Contrary to theoretical predictions (Kim and Childs 1987), the effective net damping was relatively insensitive to changes in the helix angles.
11
Редин, И. И., та М. А. Шевченко. "СИСТЕМАТИЗАЦІЯ І УЗАГАЛЬНЕННЯ ТЕОРЕТИЧНИХ ТА ЕКСПЕРИМЕНТАЛЬНИХ ДАНИХ ПО ЕФЕКТИВНОСТІ НАДРОТОРНОГО ПРИСТРОЮ В ОСЬОВОМУ КОМПРЕСОРІ". Open Information and Computer Integrated Technologies, № 87 (30 червня 2020): 181–99. http://dx.doi.org/10.32620/oikit.2020.87.11.
Анотація:
The systematization of physical flow models at the peripheral region of the rotors of axial compressor is carried out. Based on the experimental and numerical studies, the flow features in subsonic and transonic rotors are analyzed. Similar features of the flow near the wall at the periphery of subsonic and transonic rotors are formulated. The characteristic areas and individual features of the near-wall flow in them, which are obtained in experimental studies of the flow structure at the periphery of the blade rows, are reflected. The analysis of the influence of annular grooves in the axial compressor case on the flow in the airfoil channel of the subsonic and transonic rotors is presented. The hypothetical mechanism of the flow effect in the cavity of the annular groove on the main flow at the tip region of the airfoil channel of axial compressor rotor is described. An approach to generalize the experimental data of the axial compressor stages with the casing treatment based on the selected fundamental system of dimensionless parameters characterizing the main features of the flow at the rotor tip region are proposed. Using the approach, the dependences of the casing treatment effect on the gas-dynamic stability limit and efficiency are obtained. It was found, when Reynolds numbers ReΔr> 400 increase, the efficiency of annular groove casing treatment in the axial compressor wall on the gas-dynamic stability limit of the compressor decreases. The existence of the region of aerodynamic efficiency modes of the annular groove casing treatment in the case is shown. In this area, there is an optimal mode when the maximum effect of efficiency from install annular groove casing treatment is achieved. The obtained generalization al-lows us, at the step of making design decisions, to evaluate the effectiveness of the annular groove casing treatment in the case when it is used in subsonic and transonic rotors of the axial compressor stages.
12
Mawet, D., P. Riaud, O. Absil, and J. Surdej. "Annular Groove Phase Mask Coronagraph." Astrophysical Journal 633, no. 2 (November 10, 2005): 1191–200. http://dx.doi.org/10.1086/462409.
13
Rhode, D. L., J. W. Johnson, and D. H. Broussard. "Flow Visualization and Leakage Measurements of Stepped Labyrinth Seals: Part 1—Annular Groove." Journal of Turbomachinery 119, no. 4 (October 1, 1997): 839–43. http://dx.doi.org/10.1115/1.2841195.
Анотація:
An improved understanding of a new category of stepped labyrinth seals, which feature a new “annular groove,” was obtained. A water leakage and flow visualization test facility of very large scale (relative to a typical seal) was utilized. Flow visualization experiments using a new method and digital facilities for capturing and editing digital images from an 8 mm video were conducted. The presence of an annular groove machined into the stator land increases the leakage resistance by up to 26 percent for the cases considered here. Tracer particles show the degree of throughflow path penetration into the annular groove (i.e., serpentining), which gives the largest and the smallest leakage resistance improvement over that of the corresponding conventional stepped seal.
14
Wang, He, Long Quan, Jiahai Huang, Guofang Gong, and Xu Yang. "Reduction of steady flow torques in a single-stage rotary servo valve." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 233, no. 4 (August 22, 2018): 718–27. http://dx.doi.org/10.1177/0954408918793402.
Анотація:
In this paper, geometry optimization of spool is proposed to reduce the steady flow torques in a single-stage rotary servo valve. The steady flow torques under different spool structures are studied by computational fluid dynamics simulation and experimental test and the most effective spool structure is found out. Then, the effects of geometry parameters on the steady flow torques are studied and an optimized solution for reduction of the steady flow torques is suggested by considering the optimization qualities and production costs. The results show that modification of the geometry of spool can make the jet angle at the orifices much closer to 90°, with almost no effect on the flow rate. Processing annular groove in the spool land with increased number of grooves on one side of the spool land is an effective way to reduce the steady flow torques. The maximum value of steady flow torques reduces with a gradual decrease in reduction as the external diameter of annular groove and the number of grooves increase. With the optimized spool structure, the maximum value of steady flow torques can be reduced significantly.
15
Lin, Jen Fin, Sheng-Chao Chen, Yu Long Ouyang, and Ming Shih Tsai. "Analysis of the Tribological Mechanisms Arising in the Chemical Mechanical Polishing of Copper-Film Wafers When Using a Pad With Concentric Grooves." Journal of Tribology 128, no. 3 (March 8, 2006): 445–59. http://dx.doi.org/10.1115/1.2194913.
Анотація:
An average Reynolds equation considering the effects of a pad’s annular grooves and surface roughness is developed in this study to examine mixed lubrication in the chemical mechanical polishing (CMP) of a copper-film silicon wafer. This equation is obtained on the basis of the principle that the pressure gradients and volume flow rates in the direction normal to the border of a groove and a plateau as well as on two sides of the border must be equal. The continuities of volume flow rates and hydrodynamic pressure on two sides of the border as well as in the direction normal to the border of a groove and a plateau are satisfied in order to develop this Reynolds equation. The removal rate model is obtained by taking the concentration of active abrasives in the slurry and the pad grooves into account. Theoretical results are also shown in order to investigate the effects of changing the groove depth and width on the removal rate and the nonuniformity of a copper-film wafer. The application of concentric grooves in general can lower the suction pressure (negative pressure) formed between the pad and the wafer, elevate the wear rate, and reduce the nonuniformity. However, the influences of the groove depth on wear rate and nonuniformity become insignificant when the depth is excessively large. The removal rate is reduced by increasing the groove width such that it finally approaches to the result of a nongrooved pad.
16
Patrik, Šarga, Trebuňa František, and Grejták Branislav. "DESIGN OF CONTROL FOR THE DEVICE USING FOR THE DETERMINATION OF RESIDUAL STRESSES BY RING-CORE METHOD." TECHNICAL SCIENCES AND TECHNOLOG IES, no. 4 (14) (2018): 162–68. http://dx.doi.org/10.25140/2411-5363-2018-4(14)-162-168.
Анотація:
Urgency of the research. Residual stresses in machine parts and constructions greatly affect their service life and reliability. They are introduced into the manufactured object at each production process and their level can change significantly due to the operation of the product. Their main risk lies in the fact that they add up to the external load and can be the cause of the failure of the construction. Residual stresses can not be determined by simulation methods. They can only be determined using experimental methods. One of these method is the Ring-Core method, the principle of which is to form an annular groove around the strain gauge. Creating of annular groove releases the internal stresses, which can be recorded by a strain gauge. The quality of the formed groove has a significant impact on the overall results of residual stress determination, so it is important to make it as accurate as possible. For this reason, it is necessary to have the most reliable device to form an annular groove. Target setting. Our goal was to design the drive and control for the measuring device for milling the annular groove. This will make it possible to mill the annular groove more precisely, and the resulting residual stresses will be minimally affected by the inaccuracy of the groove. Actual scientific researches and issues analysis. When designing the control of the device and preparing this paper, we took into account not only current sources – publications and papers dealing with the current state of existing measuring devices used for determining residual stresses by Ring-Core method, but – we also took into account our practical experience gained in numerous residual stress determinations by experimental methods. Uninvestigated parts of general matters defining. A modified device requires thorough testing, which has not been implemented during the research for this paper. The research objective. The goal of the research was to create a control for the existing mechanical measuring device used for creating annular groove for determining residual stresses by Ring-Core method. The statement of basic materials. The original mechanical device was supplemented by actuators, which were designed to automate the movement in horizontal axes as well as in the vertical axis. Thanks to this, we have achieved greater precision when positioning the work tool above the center of the strain gauge. At the same time, the original equipment was completed with a servo motor that serves to drive the cutter. For all these elements, control by Programmable Logic Controller was proposed. Conclusions. Our task was to design control for the original device used for residual stress measurement by the RingCore method. We needed to design drives to automate the device. For our needs, we decided to apply linear actuators selected according to the requested criteria. After designing of the electric drives and modifying of the original device, we proceeded to implement control by Programmable Logic Controller. After that, we created a control program in the Automation studio software. This modified measuring device is able to achieve a much higher precision of the annular groove milling, which makes it possible to deter-mine the residual stresses in the structures more precisely
17
Dzarmotov, Sultan I., and Magomet K. Aushev. "CENTRIFUGAL PUMP ROTOR NUT." Oil and Gas Business, no. 4 (September 14, 2023): 116–26. http://dx.doi.org/10.17122/ogbus-2023-4-116-126.
Анотація:
A centrifugal pump rotor is proposed with the impeller mounted on the shaft using two nuts of fixed interacting reciprocal conical surfaces. The scientific work relates to the field of pump engineering, namely, to one of the methods of locking the rotor nut used in the design of centrifugal pumps, various self-locking devices of mechanisms and structural elements of fasteners that prevent self-unscrewing. The self-locking nut includes a nut, a solid crown with an inner conical surface interacting with the annular groove of the nut itself and with an annular conical groove on the outer surface and, moreover, on one side of the annular groove of the nut itself with a conical outer surface, and the inner conical surface of solid crown is conjugated with the outer conical surface of the nut itself. The inner conical surfaces of the solid crown are connected to the outer ones – the nut with tension.
18
Kim, Chang-Ho, and D. W. Childs. "Analysis for Rotordynamic Coefficients of Helically-Grooved Turbulent Annular Seals." Journal of Tribology 109, no. 1 (January 1, 1987): 136–43. http://dx.doi.org/10.1115/1.3261305.
Анотація:
An analysis for helically-grooved turbulent annular seals is developed to predict leakage and dynamic coefficients, as related to rotordynamics. The grooved surface pattern is formulated as an inhomogeneous directivity in surface shear stress. The governing equations, based on both Hirs’ turbulent lubrication theory and “fine-groove” theory, are expanded in the eccentricity ratio to yield zeroth and first-order perturbation solutions. The zeroth-order equations define the steady-state leakage and the circumferential velocity development due to wall shear for a centered rotor position. The first-order equations define perturbations in the pressure and axial and circumferential velocity fields due to small motion of the rotor about the centered position. Numerical results are presented for proposed grooved seals in the High Pressure Oxygen Turbopump (HPOTP) of the Space Shuttle Main Engine (SSME) and for a water-pump application. The results show that an optimum helix angle exists from a rotordynamic stability viewpoint. Further, a properly designed helically-grooved stator is predicted to have pronounced stability advantages over other currently used seals.
19
Zhang, Liang, Lan He, Yuwei Liang, Juncheng Zhang, Haiyang Zhang, Jing Zhou, Haotian Cui, Mingrui Li, Yuanyuan Miao, and Zhenbo Liu. "Modulating the Acoustic Vibration Performance of Wood by Introducing a Periodic Annular Groove Structure." Forests 14, no. 12 (November 30, 2023): 2360. http://dx.doi.org/10.3390/f14122360.
Анотація:
The acoustic vibration performance of wood affects the quality of many musical instruments, and the variability of wood causes obvious differences between individual timber samples. To mitigate the variations among the individual timber samples intended for musical instruments, in this study, we combined finite element simulation with experimental testing to investigate the effect of the periodic annular groove structure on the comprehensive acoustic vibration characteristics of wood. The results revealed that there are discernible correlations between the structural parameters of the periodic annular groove and the key acoustic parameters of wood, including the resonant frequency, equivalent dynamic modulus of elasticity, equivalent specific dynamic modulus of elasticity, equivalent acoustic radiation quality constant, and equivalent acoustic impedance. These relationships can be used to fine-tune the overall acoustic vibration performance of wood and harmonize the acoustic vibration characteristics among different timber specimens. The effects of the periodic annular groove structure on the five acoustic vibration parameters obtained through finite element simulations exhibited minimal differences to the corresponding results from experimental tests. Furthermore, there was a remarkably strong correlation between the outcomes of the finite element simulations and the experimental test results, with the coefficient of determination exceeding 0.99.
20
Li, Ying, Peng Yun Song, and Heng Jie Xu. "Performance Analyses of the Spiral Groove Dry Gas Seal with Inner Annular Groove." Applied Mechanics and Materials 420 (September 2013): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amm.420.51.
Анотація:
In order to improve the performance of the spiral groove dry gas seal (S-DGS), the spiral groove dry gas seal with an inner annular groove (AS-DGS) was invented. Based on the narrow groove theory, the sealing performance parameters of the AS-DGS were gained by using approximate analytical method to solve the gas film pressure control equations, and the results were compared with those of the common S-DGS. The results show that, in the given operating conditions, the opening force of AS-DGS is smaller than that of the S-DGS with the difference less than 0.5%, and the film stiffness is larger than that of the common S-DGS with the difference less than 5% in the case of low-speed or high-pressure operation, but the leakage is a little larger.
21
Nozu, S., and H. Honda. "Condensation of Refrigerants in Horizontal, Spirally Grooved Microfin Tubes: Numerical Analysis of Heat Transfer in the Annular Flow Regime." Journal of Heat Transfer 122, no. 1 (August 1, 1999): 80–91. http://dx.doi.org/10.1115/1.521439.
Анотація:
A method is presented for estimating the condensation heat transfer coefficient in a horizontal, spirally grooved microfin tube. Based on the flow observation study performed by the authors, a laminar film condensation model in the annular flow regime is proposed. The model assumes that all the condensate flow occurs through the grooves. The condensate film is segmented into thin and thick film regions. In the thin film region formed on the fin surface, the condensate is assumed to be drained by the combined surface tension and vapor shear forces. In the thick film region formed in the groove, on the other hand, the condensate is assumed to be driven by the vapor shear force. The present and previous local heat transfer data including four fluids (CFC11, HCFC22, HCFC123, and HFC134a) and three microfin tubes are found to agree with the present predictions to a mean absolute deviation of 15.1 percent. [S0022-1481(00)01501-2]
22
Huang, Q., S. S. Feng, X. K. Lan, C. N. Chen, and T. Zhou. "Effect of groove structure on penetration performance of annular grooved projectiles impacting metal targets." IOP Conference Series: Materials Science and Engineering 629 (October 8, 2019): 012022. http://dx.doi.org/10.1088/1757-899x/629/1/012022.
23
Alukayli, Mahmoud, Satoru Fujii, Jill Gelinas, Chris Harle, Rodrigo Bagur, and Michael W. A. Chu. "Hybrid Double Valve Replacement for Multivalvular Disease With Severe Mitral Annular Calcification." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 16, no. 2 (January 22, 2021): 198–200. http://dx.doi.org/10.1177/1556984520986934.
Анотація:
Severe mitral annular calcification poses a significant challenge, particularly in higher risk, frail, elderly patients with multivalvular disease. Both surgical and transcatheter options exist but remain fraught with risks of paravalvular leak, atrioventricular groove disruption, patient prosthesis mismatch, and left ventricular outflow tract obstruction. We present an innovative hybrid surgical approach to manage severe aortic and mitral valve disease in a Jehovah’s Witness patient with severe circumferential mitral annular calcification.
24
Sokhan’, S. V., V. V. Voznyy, and V. H. Sorochenko. "Diamond Grinding of Ceramic Balls in an Annular Groove." Journal of Superhard Materials 46, no. 2 (April 2024): 143–53. http://dx.doi.org/10.3103/s1063457624020096.
25
Arghir, Mihai, and Jean Frene. "A Bulk-Flow Analysis of Static and Dynamic Characteristics of Eccentric Circumferentially-Grooved Liquid Annular Seals." Journal of Tribology 126, no. 2 (April 1, 2004): 316–25. http://dx.doi.org/10.1115/1.1611499.
Анотація:
The bulk-flow equations used for inertia dominated thin-film flows is an attractive model for the analysis of circumferentially grooved annular seals because the solutions based on the numerical integration of the complete Navier-Stokes equations can be very time-consuming. By using three types of control volumes and some user-tuned constants, the bulk-flow model can be used for calculating the static and the dynamic characteristics. Until now, this has been carried out for centered seals where the flow is governed by ordinary differential equations but no solutions have yet been given for eccentric working conditions. In this latter case, the model is governed by partial differential equations of an elliptic type. The main problem is that for describing the groove effects, the pressure field must incorporate the concentrated drop or recovery effects that occur at the interface between the groove and the land zone. This means that the numerical procedure used for solving the elliptic equations should be able to handle a pressure field having discontinuous values and discontinuous first order derivatives. In the present work, the method used for integrating the system of bulk-flow equations is the SIMPLE algorithm. The algorithm is extended for handling pressure jumps by adding two pressure values on each side of the discontinuity. These values are then expressed in terms of cell centered pressures by imposing the mass conservation and the generalized Bernoulli equation at the discontinuity. This numerical solution is original and has never previously been presented in the finite volume related literature. Comparisons between the numerical predictions (leakage flow rate and rotordynamic coefficients) and experimental data taken from the literature Marquette and Childs (1997) are subsequently presented for an eccentric ten-groove annular seal.
26
Fan, Yu, Haonan Wang, Liangtao Xie, Nao Hu, and Jianguo Yang. "Armature Structure Optimization of Annular Multipole Solenoid Valves Based on Electromagnetic Force Distribution." Actuators 12, no. 2 (January 26, 2023): 54. http://dx.doi.org/10.3390/act12020054.
Анотація:
To improve the dynamic response speed of high-speed solenoid valves in electric fuel injection systems of marine diesel engines, a numerical simulation model of the solenoid valve is described in this paper. The accuracy of the simulation model was verified on the test bed of the solenoid valve. The effect of the punch position and the size of the dynamic response of the solenoid valve were investigated by using the distribution law of the electromagnetic force in the armature. The results of the test showed that armature drilling in the inter-yoke zone can optimize the solenoid closing response time, but it has little impact on the solenoid opening response time. From this rule, two groove schemes were further designed. Through comparison and calculation, it can be concluded that the fan groove scheme is better than the trapezoidal groove scheme, and that the opening and closing response times of the solenoid valve should be targeted in order to multi-target optimize the fan groove geometric parameters and the armature thickness. The results show that after optimization, the weight of the motion part is reduced by 21.6%, the opening response time of the solenoid valve is reduced by 11.1%, and the closing response time is reduced by 30.0%. While reducing the oil film damping of the armature motion, the overall dynamic response characteristics of the solenoid valve are improved.
27
Jiang, Xue, Yan Yu, Yuan Zhang, and Pei Pei Su. "Simulation Analysis of Friction Disc Temperature Field of Hydro-Viscous Variable Speed Clutch." Applied Mechanics and Materials 220-223 (November 2012): 705–9. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.705.
Анотація:
Hydro-viscous variable speed clutch transmits torque by means of viscous fluid between the friction discs. The study of temperature distribution on friction disc plays a very important role for the design of hydro-viscous soft-start device. When the grooves on the driving friction disc surface have more complex shape, the analytic solution of the temperature field is difficult to obtain. By the advantage of the periodicity of geometric dimension along the circumferential direction of the driving friction disc, physical model with radial and annular groove is simplified and built. FLUENT software is used to make a simulation analysis on the temperature field of the friction disc, transient and steady state temperature distribution is obtained which provides a new approach to the analysis of the temperature field of the friction disc with complex grooves.
28
Wang, Jin, Jialin Zhang, Zhanyang Yu, Jianmin Du, and Yan Li. "Analytical Modeling for Magnetic Field Calculation of SPMSM Based on Equivalent Magnetic Network Method." Journal of Physics: Conference Series 2179, no. 1 (January 1, 2022): 012019. http://dx.doi.org/10.1088/1742-6596/2179/1/012019.
Анотація:
Abstract In order to quickly calculate electromagnetic parameters and reduce total harmonics distortions (THD) of air-gap flux density for surface-mounted permanent magnet synchronous motor (SPMSM), the equivalent magnetic network method (EMNM) is used. Compared with traditional magnetic circuit method, the calculation result is more accurate and the calculation speed is faster than finite element method FEM). The EMNM considering the stator groove shape and core saturation is established by piecewide fitting of annular equivalence and magnetic ring curve formulas of the groove fan. The accuracy of EMNM is verified by FEM.
29
Qiu, Y., and M. M. Khonsari. "Investigation of tribological behaviors of annular rings with spiral groove." Tribology International 44, no. 12 (November 2011): 1610–19. http://dx.doi.org/10.1016/j.triboint.2011.05.008.
30
Choi, Young-Do, and Ujjwal Shrestha. "Cavitation Performance Improvement of an Annular Jet Pump by J-Groove." KSFM Journal of Fluid Machinery 23, no. 4 (August 31, 2020): 25–35. http://dx.doi.org/10.5293/kfma.2020.23.4.025.
31
Wang, Liang, Zhong Yun, Xiaoyan Tang, and Chuang Xiang. "Influence of circumferential annular grooving design of impeller on suspended fluid force of axial flow blood pump." International Journal of Artificial Organs 45, no. 4 (January 10, 2022): 360–70. http://dx.doi.org/10.1177/03913988211064912.
Анотація:
Aiming at insufficient suspension force on the impeller when the hydraulic suspension axial flow blood pump is start at low speed, the impeller suspension stability is poor, and can’t quickly enter the suspended working state. By establishing the mathematical model of the suspension force on the impeller, then the influence of the circumferential groove depth of the impeller on the suspension force is analyzed, and the annular groove depth on the impeller blade in the direction of fluid inlet and outlet was determined as (0.26, 0.02 mm). When the blood pump starts, there is an eccentricity between the impeller and the pump tube, the relationship between the suspension force and the speed of the impeller under different eccentricities is analyzed. Combined with the prototype experiment, the circumferential annular grooving design of the impeller can make the blood pump rotate at about 3500 rpm into the suspension state, when the impeller is at 8000 rpm, the impeller can basically achieve stable suspension at the eccentricity of 0.1 mm in the gravity direction, indicating that the reasonable circumferential annular grooving design of the impeller can effectively improve the suspension hydraulic force of the impeller and improve the stability of the hydraulic suspension axial flow blood pump.
32
Tan, Wuzhong, Zhi Chen, Zhizuo Li, and Hongzhi Yan. "Thermal-Fluid-Solid Coupling Simulation and Oil Groove Structure Optimization of Wet Friction Clutch for High-Speed Helicopter." Machines 11, no. 2 (February 16, 2023): 296. http://dx.doi.org/10.3390/machines11020296.
Анотація:
Wet friction clutch is the key functional component of the high-speed helicopter variable-speed transmission system, which is used to change the power transmission path. In the engagement process of wet friction clutch, the driving/driven disc will produce drag torque under the shearing of lubricating oil, which reduces the transmission efficiency. This unnecessary drag torque reduces efficiency and increases clutch temperature. The temperature increase promotes the wear of gears and bearings and the aging deformation of friction plates, which leads to local wear and reduces the service life of the clutch. From the principle of wet friction clutch, the oil groove structure is directly related to the drag torque and the temperature rise of friction disc. It is very important for the long-distance flight and service life of high-speed helicopters to obtain the groove structure with low drag torque and low temperature rise. In order to solve this problem, taking the wet friction clutch of a high-speed helicopter as the research object, based on the radial and annular compound groove, the thermal-fluid-solid coupling simulation model of the wet friction clutch is established to obtained the flow characteristics and temperature field distribution of the lubricating oil in the friction disc oil groove, and to analyze the influence law of the oil groove structure parameters on the drag torque and temperature field. In order to improve the transmission efficiency and the service life of friction disc, Taguchi experiment and non-dominated neighborhood immune algorithm were used to optimize the structural parameters of the oil grooves. The comparison results show that the optimized structural can effectively reduce the drag torque and the temperature rise. This work can provide a theoretical reference for the structure design of a wet friction clutch.
33
Emami, Reza, Elahe Sadat Alavi Moghadam, and Mostafa Sohrabi. "Crashworthiness Optimization of Thin Walled Cylindrical Tubes with Annular Grooves under Axial Compression." Advanced Materials Research 463-464 (February 2012): 30–35. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.30.
Анотація:
In this paper explicit finite element codes of LS DYNA are applied to simulate the crushing behavior of cylindrical metallic impact energy absorbers with annular machined grooves and the validation of the simulation results are done by comparing with experimental and theoretical findings from the literature. Some efforts are made to find the optimum groove geometry of the tubes by considering two criteria such as the maximum absorbed energy per unit mass (SEA) and maximum ratio of average load to maximum load during crushing (CFE). Maximum allowable load during crushing and the geometrical limits that should not exceed some specified boundaries are considered as design constrains. Based on design of experiment technique (DOE) the conditions that the results should be taken are determined and consequently, response surface (RS) models are created to build a composite objective function that considers both CFE and SEA. Genetic algorithm is applied to find the optimal point for the composite function that meets the design requirements.
34
Xu, Lishan, Weizheng Zhang, Junjie Lu, and Zhu Liu. "Influence of Floating Ring Seal Working Condition Parameters on the Dynamic Characteristics of Transient Gas Film." Journal of Physics: Conference Series 2108, no. 1 (November 1, 2021): 012087. http://dx.doi.org/10.1088/1742-6596/2108/1/012087.
Анотація:
Abstract The high requirements for sealing performance in high-speed rotating machinery has led to the design of floating seal with annular spiral groove that offer the advantages of low leakage and extended stability. However, efforts to model the dynamic performance of these floating seal have suffered from the great complexity of the flow field. The present work addresses this issue by establishing a transient Reynolds formulation of a floating seal with annular spiral groove in a rotating coordinate system based on the small perturbation method. In addition, the influence of radial eccentricity and film thickness on the solution divergence and calculation accuracy is calculated. The dynamic stiffness and dynamic damping matrixes are built. Then the variation rules of the dynamic stiffness and damping coefficient of the gas film with structure and working conditions are investigated in detail. The results show that the floating ring seal is more suitable for the service conditions of small film thickness, low pressure, high speed and large eccentricity. Accordingly, the results obtained lay a theoretical foundation for evaluating real-world applications of floating ring seal.
35
Zhang, Donghui, Lili Sun, Jijin Mao, Qinhui Lei, Daifen Chen, and Alexey P. Levtsev. "Flow Boiling Heat Transfer of Grooved Copper Foam with Open Gap." Engineering Technologies and Systems 32, no. 3 (September 30, 2022): 423–36. http://dx.doi.org/10.15507/2658-4123.032.202203.423-436.
Анотація:
Introduction. Copper foam material has various advantages. It has been proved effective in enhanced boiling heat transfer, but also increases pump power consumption. Grooved copper foam is a solution to achieve good balance between boiling heat transfer characteristics and pump power consumption. Material and Methods. Grooveless and grooved copper foam in open space was studied. Copper foam specifications comprised the combination of porosities of 70, 80 and 90%, and pore densities of 90 and 110 PPI. The grooved copper foams have two specifications: 11 and 17 grooves. The corresponding rib widths are 2 and 1 mm, with groove depth 2.9 mm and width 0.6 mm. The flow boiling experimental system of copper foam sample includes four parts: a heating water reservoir, pump, a test section, and a data acquisition system. In the test section, liquid water turns into vapor and carries the heat away from a copper block surface, and then vapor condenses into liquid water in the terminal reservoir. Results. Grooved copper foam samples presented significantly higher efficiency than grooveless ones. Grooved copper foams can increase the critical heat flux and heat transfer coefficient, compared with grooveless ones. Seventeen-grooved samples showed more excellent performance than 11-grooved ones. Visual observation disclosed that the stratified flow pattern dominated in moderate and high heat flux for grooved copper foam with open space. Covering vapor mass was more effective to be formed above 17-grooved samples, compared with 11-grooved ones. It indicated more vigorous boiling behavior occurs in 17-grooved sample. Discussion and Conclusion. The number of grooves has a significant impact on boiling heat transfer. Grooved copper foam samples present a significantly higher critical heat flux and heat transfer coefficient. Structural parameters such as porosity and pore density, play a relatively secondly role in heat transfer argumentation. Visual observation shows there exists a cyclic alternation of flow patterns: bubbly flow, annular flow and mass vapor formation for grooved samples. Forming vapor mass is more effective to be formed in 17-grooved samples, compared to 11-grooved ones. It indicates more vigorous boiling behavior occurs in 17-grooved samples.
36
SASAKI, Kazuaki, Hiroyuki KATO, and Tomosato YAMAGUCHI. "Stress Analysis of Axisymmetric Bar with Annular Groove in Micropolar Elasticity." Proceedings of Conference of Hokkaido Branch 2003.43 (2003): 4–5. http://dx.doi.org/10.1299/jsmehokkaido.2003.43.4.
37
Huang, Kuilin, Zhijiu Ai, Yingxin Yang, and Zongliang Xie. "The improved rock breaking efficiency of an annular-groove PDC bit." Journal of Petroleum Science and Engineering 172 (January 2019): 425–35. http://dx.doi.org/10.1016/j.petrol.2018.09.079.
38
Balaguru, S., Kumar Shashi, Murali Vela, and P. Chellapandi. "Thermo Mechanical Analysis of SS304 Circular Grid Plate Hard Faced with Colmonoy." Applied Mechanics and Materials 229-231 (November 2012): 710–17. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.710.
Анотація:
In this paper, plasma transfer arc welding using hard faced material Colmonoy which is deposited on a annular groove of a circular grid plate made up of SS 304 was studied. Hard face deposition made by Plasma Transferred Arc Welding (PTAW) on a annular groove of a grid plate at relatively high temperature, generates residual stresses due to differential shrinkage of the molten deposit, process-induced thermal gradients and difference in coefficients of thermal expansion between the colmonoy deposit and base material SS 304. However, the magnitude and distribution of the residual stresses vary depending on the heat input, deposition process, and the geometry of the component. Finite element analysis of residual stress is performed with commercial FEA package of ANSYS 12.0 which includes moving heat source, material deposit, temperature dependent material properties, metal plasticity and elasticity. Coupled thermo-mechanical analysis is done for welding simulation and the element birth and death technique is employed for simulation of filler metal deposition. Finally residual stress is evaluated so that annealing is performed accordingly to relieve residual stresses in order to carry out fracture analyses thereafter.
39
Gao, Yang, Jiachao Zhang, Zhihu Ruan, Lin Meng, and Jia Jia. "Shape, Resonant Frequency and Thermoelastic Dissipation Analysis of Free-Formed Microhemispherical Shells Based on Forming Process Modeling." Micromachines 13, no. 6 (June 9, 2022): 913. http://dx.doi.org/10.3390/mi13060913.
Анотація:
Free-form microhemispherical shell resonators have the advantages of high quality factor and mass production. The shape of microhemispherical shells created via this process is based on a single mold and is difficult to adjust, which affects the resonant frequency and quality factor. In this paper, a process analysis model is established through in-depth analysis of the process mechanism and flow of the free-forming method. Based on this model, the influence of the designed preforming parameters on the shape, resonant frequency and thermoelastic dissipation of the microhemispherical shell are analyzed in detail, providing theoretical guidance for parameter design. The results show that the depth and the ratio of internal to external pressure of the substrate’s annular groove affect the height and thickness of the microhemispherical shell, and the structural thickness affects the thickness of the microhemispherical shell; these in turn affect the resonant frequency and thermoelastic dissipation of the microhemispherical shell resonator. In addition, the inner diameter of the substrate’s annular groove mainly affects the radius of the support column of the microhemispherical shell, and the influence on the resonant frequency and thermoelastic dissipation of the resonator is relatively low.
40
Shrestha, Ujjwal, and Young-Do Choi. "Estimation of Reverse Flow Rate in J-Groove Channel of AJP and SCP Models Using CFD Analysis." Processes 10, no. 4 (April 16, 2022): 785. http://dx.doi.org/10.3390/pr10040785.
Анотація:
An annular jet pump (AJP) and a screw centrifugal pump (SCP) are special-purpose pumps used for transportation. The flow fields in the AJP and SCP are like those in a diffuser without and with an impeller, respectively. The flow from diffuser inlet to outlet takes place via the conversion of kinetic energy to static pressure. J-Groove is installed in the diffuser wall of an AJP and SCP to induce reverse flow from the diffuser outlet to the inlet, which suppresses the cavitation. CFD analysis was carried out to verify the conceptual design and understand the internal flow field of an AJP and SCP with J-Groove. The CFD analysis showed that the J-Groove installation in the AJP and SCP improved suction performance. The reverse flow in the J-Groove is due to the pressure difference between the diffuser outlet and the inlet. The numerical analysis results showed that the reverse flow mechanism is dependent on the flow conditions, cavitation number, and presence of the impeller. In a higher flow rate, the reverse flow rate is higher in the AJP model and lower in the SCP model and vice versa. Finally, CFD analysis concluded that the reverse flow rate in J-Groove improves the suction performance of the AJP and SCP models.
41
Албул, С. В., О. А. Кобелев, and И. А. Левицкий. "EFFECT OF SURFACE RELIEF OF HEAT-INSULATING INSERT IN BLAST CHANNEL OF BF TUYERE ON EFFICIENCY OF ITS OPERATION." Metallurg, no. 3 (September 14, 2023): 78–83. http://dx.doi.org/10.52351/00260827_2023_03_78.
Анотація:
При подаче природного газа в воздушную фурму доменной печи необходимо стремиться, с одной стороны, к увеличению полноты прохождения реакции горения природного газа внутри дутьевого канала фурмы и, с другой стороны, к защите внутреннего стакана фурмы от прогара. Одним из способов одновременного решения этих проблем является установка в дутьевой канал фурмы теплоизолирующей керамической вставки. В данной работе рассматривается возможность повышения эффективности применения керамической вставки путем образования на ее поверхности рельефа в виде одной или нескольких кольцевых выборок (канавок) для улучшения перемешивания природного газа с дутьем с целью увеличения полноты прохождения реакции горения. В среде Ansys 21.1 моделируются процессы движения текучих сред, теплообмена и горения природного газа в дутьевом канале фурмы доменной печи с установленной в него керамической вставкой, имеющей кольцевые выборки четырехугольного сечения. Исследовано влияние глубины и ширины выборки, а также расстояния между выборками на происходящие в фурме процессы. Показано, что создание кольцевой выборки на внутренней поверхности вставки приводит к росту суммарного количества теплоты, выделившейся в результате интенсификации горения природного газа, что подтверждается ростом содержания СО2, температуры и скорости дутья на выходе из фурмы. Максимальные температурные напряжения во вставке при этом тоже увеличиваются, однако, они превышают максимальные напряжения во вставке при отсутствии выборки не более, чем на 30%. When supplying natural gas to the blast furnace tuyere, it is necessary to strive to achieve two contradictory goals: to increase the completeness of the passage of natural gas combustion reaction inside the blast channel of the tuyere and to protect the inner nozzle of the tuyere from burnout. One of the ways to simultaneously solve these problems is to install a heat-insulating ceramic insert in the blast channel of the tuyere. In this paper, we consider the possibility of increasing the efficiency of using a ceramic insert by forming a relief on its surface in the form of one or more annular grooves to improve the mixing of natural gas with blast in order to increase the completeness of the combustion reaction. In this work in Ansys 21.1 software we simulate the processes of movement of fluids, heat transfer and combustion of natural gas in the blast channel of a blast furnace tuyere with a ceramic insert installed in it, which has annular quadrangular grooves, including those filled with slip coating. The influence of the depth and width of the groove, as well as the distance between the grooves, on the processes occurring in the tuyere was studied. It is shown that the creation of an annular groove on the inner surface of the insert leads to an increase in the total amount of heat released as a result of the intensification of natural gas combustion, which is confirmed by an increase in the CO2, temperature and blowing speed at the outlet of the tuyere. In this case, the maximum thermal stresses in the insert also increase, but they exceed the maximum stresses in the insert in the absence of grooves by no more than 30%.
42
Xu, HanYang, Yulong Zhao, Kai Zhang, Zixi Wang, and Kyle Jiang. "A Deformation of a Mercury Droplet under Acceleration in an Annular Groove." Biosensors 10, no. 6 (June 9, 2020): 61. http://dx.doi.org/10.3390/bios10060061.
Анотація:
Microelectromechanical system (MEMS) liquid sensors may be used under large acceleration conditions. It is important to understand the deformation of the liquid droplets under acceleration for the design and applications of MEMS liquid sensors, as this will affect the performance of the sensors. This paper presents an investigation into the deformation of a mercury droplet in a liquid MEMS sensor under accelerations and reports the relationship between the deformation and the accelerations. The Laminar level set method was used in the numerical process. The geometric model consisted of a mercury droplet of 2 mm in diameter and an annular groove of 2.5 mm in width and 2.5 mm in height. The direction of the acceleration causing the droplet to deform is perpendicular to the direction of gravity. Fabrication and acceleration experiments were conducted. The deformation of the liquid was recorded using a high-speed camera. Both the simulation and experimental results show that the characteristic height of the droplets decreases as the acceleration increases. At an acceleration of 10 m/s2, the height of the droplet is reduced from 2 to 1.658 mm, and at 600 m/s2 the height is further reduced to 0.246 mm. The study finds that the droplet can deform into a flat shape but does not break even at 600 m/s2. Besides, the properties of the material in the domain surrounding the droplet and the contact angle also affect the deformation of the droplet. This work demonstrates the deformation of the liquid metal droplets under acceleration and provides the basis for the design of MEMS droplet acceleration sensors.
43
FUKUSHIMA, Kota, Hiroyuki KATO, and Kazuaki SASAKI. "106 Axisymmetric Torsion of an Axis with Annular Groove in Micropolar Elasticity." Proceedings of Conference of Hokkaido Branch 2011.50 (2011): 11–12. http://dx.doi.org/10.1299/jsmehokkaido.2011.50.11.
44
Kishida, M., K. Sasaki, and S. Ishii. "Torsion of a circular bar with annular groove in couple-stress theory." International Journal of Engineering Science 28, no. 8 (January 1990): 773–81. http://dx.doi.org/10.1016/0020-7225(90)90022-b.
45
Qiao, Yu Jing, Rui Luo, and Ke Jian Shi. "Analysis on the Influence for the Sectional Shape of Compound Pressure-Equalizing Groove to the Supporting and Bearing Characteristics of Precision Aerostatic Bearing." Applied Mechanics and Materials 494-495 (February 2014): 598–601. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.598.
Анотація:
Static bearing capacity and static stiffness of pressure equalizing groove cross section with the same width and depth are researched in this paper, it can conclude that the trapezoidal section has the maximum static bearing capacity and static stiffness, while air consumption rate of unit load is the lowest. When compound structure annular hydrostatic thrust bearing has had the optimizing parameters, compared with the single structure one, the bearing capacity had a substantial increasing.
46
Yoshimoto, S., Y. Yoshida, and K. Yagi. "The Seal System in Aerostatic Journal Bearings for High Vacuum Chambers." Journal of Tribology 126, no. 2 (April 1, 2004): 310–15. http://dx.doi.org/10.1115/1.1611498.
Анотація:
This paper investigates the performance of a seal system for an aerostatic journal bearing used in a high vacuum chamber. The seal system consists of axially spaced viscous seals and annular exhaust grooves that are located between the viscous seals. Each exhaust groove is coupled to a separate vacuum pump in order to achieve a vacuum chamber pressure of less than 10−3 Pa. The vacuum chamber pressure is affected by design parameters such as the number of viscous seal stages, seal length, seal gap, and exhaust tube conductance. The influence of these design parameters on the pressure distribution across seal regions and the vacuum chamber pressure are discussed theoretically. It is subsequently shown that an aerostatic journal bearing with three-stage seal system installed can obtain a reduction in the vacuum chamber pressure almost to the ultimate pressure of a vacuum pump, providing there is no leak or outgassing from materials.
47
Редин, Иван Иванович, та Михаил Анатольевич Шевченко. "ДІАГНОСТИКА ПЕРЕДПОМПАЖНОГО СТАНУ ОСЬОВОГО КОМПРЕСОРА З НАДРОТОРНИМ ПРИЛАДОМ". Aerospace technic and technology, № 8 (25 грудня 2018): 97–107. http://dx.doi.org/10.32620/aktt.2018.8.15.
Анотація:
Ensuring the gas-dynamic stability of gas turbine engine, still remains one of the actual problem of modern aircraft engine building. To date, a significant number of studies have been conducted. This studies are the foundation for different techniques of diagnosing the pre-surge condition condition. Also known that one of the ways to solve the problem of increasing gas-dynamic stability is the use of casing treatment. However, there are no clearly formulated techniques that allow diagnosing the surge line in an axial compressor with casing treatment. Consequently, the problem of their development is relevant. The paper addresses the results of experimental and computational studies of unsteady flows in an axial compressor with the casing treatment in the form of annular grooves. Specific features of the transition to the regime of rotating stall (with break of the compressor characteristic) by an axial compressor with the annular grooves are formulated. The temporary conditions are provided for the formation of the reliable diagnostic signal of the axial compressor pre-surge operating mode with the annular grooves casing treatment by stabilization of the partial rotating stall condition were displayed. Calculation techniques for estimating informative criteria for detecting of the compressor pre-surge condition were proposed. One of them is the appearance of a discrete component of the amplitude-frequency characteristic of the total pressure pulsations (in the direction of rotation of the rotor) in the cavity of the groove of the casing treatment located above the leading edge of the blades. This discrete component appears at the frequency of a single-zone rotating stall, so it can serve as a trigger pulse for surge prevention automatic control system. The second informative criterion is the appearance of the gradientless region in the distribution of pressure on the bounding wall of the airgas channel above the blade. The position of the gradientless section in the pressure distribution on the bounding wall of the airgas channel above the blade with respect to the meridional projection of the chord of the tip end of the blade has been determined experimentally and by calculation according to the developed technique. Comparison of the proposed mathematical models with experimental data was performed. Their qualitative and quantitative conformity to the experiment were shown.
48
Guo, An Nan, Xiao Jing Wang, Shen Gang, and Deng Feng Jiang. "Numerical Analysis of Annular Seal with Different Distribution of Surface Texture." Key Engineering Materials 642 (April 2015): 66–71. http://dx.doi.org/10.4028/www.scientific.net/kem.642.66.
Анотація:
Surface texturing has been shown to reduce friction and increase the film thickness in various tribological applications (hydrodynamic bearings, mechanical seals, and cylinder-liner contacts). Studies have reported that surface-texture can reduce the resistance of sliding friction pair, increase the oil film thickness, increase the bearing’s capacity. Surface texture structure’s design and layout are very important, unfavorable design may lead to be counterproductive. In this paper, in combination with the 650mm seal structure, we are using the main design of groove type to seal the inner surface texture, so as to study the geometry structure and distribution's influence on seal property.
49
Noda, Nao-Aki, Masato Nagawa, Fumitaka Shiraishi, and Akifumi Inoue. "Sealing Performance of New Gasketless Flange." Journal of Pressure Vessel Technology 124, no. 2 (May 1, 2002): 239–46. http://dx.doi.org/10.1115/1.1464876.
Анотація:
This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The condition whether the system leaks or not depends on the shape and dimension of the annular lip and its deformation during the contact. In this study, several gasketless flanges are prepared with different lip dimensions to investigate the contact and sealing condition through an experimental and FEM analyses. The analyses indicate that the conditions can be expressed in terms of the maximum contact stress and the plastic zone size when the flanges are assembled. The helium leak testing reveals that the gasketless flange has better sealing performance compared to conventional gaskets.
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Yan, Jun, Litao Zhang, Linjuan Xu, Sainan Chen, Guanghong Peng, and Meng Wang. "Three-Dimensional Numerical Simulation of Flow Structure in Annular Flume Based on CFD Study of Water." Water 15, no. 4 (February 7, 2023): 651. http://dx.doi.org/10.3390/w15040651.
Анотація:
The annular flume is an ideal hydrodynamic test device for studying river sediment, and it has been widely used in recent years to study the movement patterns of sediment and other particulate matter. Annular flumes have made outstanding contributions to research in fields related to sediment transport and the diffusion and migration of pollutants. The existence of circumfluence structures in annular flumes leads to complex and variable flow structures. To obtain a more stable and controllable water flow structure, a sophisticated three-dimensional mathematical model based on the Fluent software was established to study the development law of water flow structure in the flume by changing the size of the annular flume speed ratio. The results show the following: (1) The overall trend of the simulation results basically matched with the measured results; the average relative error was 3.54% and the Nash efficiency coefficient was 0.9934, close to 1. The model calculation data were highly credible. (2) The axial flow velocity of the water tank gradually showed a “U”-shape distribution with the increase in the speed ratio. (3) When the speed ratio was R ≤ 0.17 (where the speed ratio R refers to the ratio of annular groove to shear ring speed), there was only one vortex in the tank; when the speed ratio was R > 0.17, there were multiple vortices in the tank, and the flow pattern was more complicated. (4) When the rotational speed ratio R = 0.28, the secondary flow intensity of the annular flume reached the lowest point, which was only 39.28% of the secondary flow intensity of the conventional annular flume. (5) It was determined that the annular flume water flow structure was most stable and controllable when the rotational speed ratio R = 0.24. The results of the study can provide a further theoretical basis for research on sediment dynamics and its related fields conducted by applying an annular flume.