Academic literature on the topic 'On-line path correction'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'On-line path correction.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "On-line path correction"
1
Sun, Shujie, Dong Yu, Changhui Wang, and Chuanning Xie. "A smooth tool path generation and real-time interpolation algorithm based on B-spline curves." Advances in Mechanical Engineering 10, no. 1 (January 2018): 168781401775028. http://dx.doi.org/10.1177/1687814017750281.
Full textAbstract:
In the machining progress of free-form surface, tool path is presented as continuous small line segments. To achieve high machining speed and fine machining quality, the tool path needs to be smoothed. This study presents a smooth tool path generation algorithm based on B-spline curves for small line segments machining. The algorithm includes two modules: smooth tool path generation module and real-time look-ahead interpolation module. In the smooth tool path generation module, the tool path is divided into non-fitting regions and fitting regions by three conditions: the length of small line segments, the angle of adjacent small line segments, and the change rate of the length and angle. To control contour error and get fine machining quality, the fitting regions are corrected by circle correction method and fitted into B-spline curves, while the non-fitting regions are smoothed with B-spline curves. In this module, the gained tool path has continuous curvature. In the interpolation module, the seven-phase jerk-limited look-ahead planning is adopted to generate smooth machining velocity, while the calculation accuracy of interpolation point generated by the interpolation period crossing two adjacent tool path is controlled. Simulations and experimental results demonstrate that the proposed algorithm is able to reduce the amount of numerical control codes, achieve high machining speed, and improve machining quality.
2
Belchior, Jérémy, Dominique Guines, Lionel Leotoing, and Eric Ragneau. "Force Prediction for Correction of Robot Tool Path in Single Point Incremental Forming." Key Engineering Materials 554-557 (June 2013): 1282–89. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1282.
Full textAbstract:
In this work, an off-line compensation procedure, based on an elastic modelling of the machine structure coupled with a Finite Element Analysis (FEA) of the process is applied to Robotized Single Point Incremental Forming (RSPIF). Assuming an ideal stiff robot, the FEA evaluates the Tool Center Point (TCP) forces during the forming stage. These forces are then defined as an input data of the elastic robot model to predict and correct the tool path deviations. In order to make efficient the tool path correction, the weight of three numerical and material parameters of the FEA on the predicted forces is investigated. Finally, the efficiency of the proposed method is validated by the comparison between numerical and experimental geometries obtained with or without correction of the tool path.
3
Frehlich, Rod, Robert Sharman, Charles Clough, Michael Padovani, Kelly Fling, Ward Boughers, and W. Scott Walton. "Effects of Atmospheric Turbulence on Ballistic Testing." Journal of Applied Meteorology and Climatology 47, no. 5 (May 1, 2008): 1539–49. http://dx.doi.org/10.1175/2007jamc1775.1.
Full textAbstract:
Abstract The effects of atmospheric turbulence on munition target scatter are determined from numerical simulations of ballistic trajectories through many realizations of realistic simulated turbulent wind fields. A technique is evaluated for correcting for the effects of turbulence on ballistic testing procedures by using a line of sonic anemometer measurements taken along the trajectory path. The metric used to evaluate the correction is the difference between the target impact scatter produced with and without the use of the anemometers in the trajectory calculations. The improvement in the testing procedure as measured by this metric is determined as a function of the number of sonic anemometers in the line and the sonic averaging time interval. The performance of the simulations is also compared with data from a field test for a standard small-caliber munition, and the predicted and observed target scatter are in good qualitative agreement, supporting the feasibility of the approach.
4
Qiu, Changwu, Qixin Cao, and Shouhong Miao. "An on-line task modification method for singularity avoidance of robot manipulators." Robotica 27, no. 4 (July 2009): 539–46. http://dx.doi.org/10.1017/s026357470800492x.
Full textAbstract:
SUMMARYIn this paper, we present an on-line task modification method (OTMM) to realize singularity avoidance for nonredundant and redundant manipulators at the velocity level. The method introduces a correction vector, constructed from the task velocity and the singular vector corresponding to the minimum singular value, into the task velocity. The performance is simply affected by the choice of the lower limit of the minimum singular value and a scalar adjusting function, which is monotone with respect to the minimum singular value. The method makes unnecessary avoiding the singularity point by off-line path planning for nonredundant or redundant manipulators, and the effort to check whether the singularity is escapable for redundant manipulators. The simulation results show the effectiveness of the OTMM for on-line singularity avoidance in manipulator motion control.
5
Li, Meng, Kanhua Su, Shuli Hu, Lifu Wan, and Weiqing Chen. "Displacement vectors control method for orienter ribs during path correction in coiled tubing drilling." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 10 (December 12, 2018): 3531–46. http://dx.doi.org/10.1177/0954406218819036.
Full textAbstract:
The well path easily deviates from the original design trajectory during coiled tubing drilling, which needs to be corrected with an orienter. A three-segment correction trajectory with two arc segments and a line segment is constructed based on the differential geometry principle, and the direction at the target is consistent with the direction of the original borehole. Based on the parameters of the design correction trajectory, a mathematical relationship between trajectory parameters and the displacement vectors of orienter ribs is established by using the vector analysis method. According to the principle of minimum energy, the problem of multisolvability in mathematics is avoided. Then, the control model of the displacement vectors of orienter ribs with the parameters' variation of the designed correction trajectory is established. The similarly periodic variation rule of displacements of orienter ribs with the variation of tool face angle is obtained, and the closed-loop control scheme for correction trajectory while drilling is made. The results of field test show that by using coiled tubing drilling, during the circular arc section of the designed three-segment correction trajectory, the displacement vectors of orienter ribs vary similarly periodically, which is called the directional drilling mode. During drilling in the slanted segment, the displacements of each rib are equal, which is called the keeping drilling mode. The design method of correction trajectory and the displacement vector control method of the orienter ribs are practicable during path correction in coiled tubing drilling, which is helpful to improve the efficiency of coiled tubing drilling.
6
Sahni, Narinder Singh, Tomas Isaksson, and Tormod Næs. "Comparison of Methods for Transfer of Calibration Models in Near-Infared Spectroscopy: A Case Study Based on Correcting Path Length Differences Using Fiber-Optic Transmittance Probes in In-Line Near-Infrared Spectroscopy." Applied Spectroscopy 59, no. 4 (April 2005): 487–95. http://dx.doi.org/10.1366/0003702053641522.
Full textAbstract:
This article addresses problems related to transfer of calibration models due to variations in distance between the transmittance fiber-optic probes. The data have been generated using a mixture design and measured at five different probe distances. A number of techniques reported in the literature have been compared. These include multiplicative scatter correction (MSC), path length correction (PLC), finite impulse response (FIR), orthogonal signal correction (OSC), piecewise direct standardization (PDS), and robust calibration. The quality of the predictions was expressed in terms of root mean square error of prediction (RMSEP). Robust calibration gave good calibration transfer results, while the other methods did not give acceptable results.
7
Guo, Yan, Aiguo Song, Jiatong Bao, Tang Hongru, and Jianwei Cui. "A Combination of Terrain Prediction and Correction for Search and Rescue Robot Autonomous Navigation." International Journal of Advanced Robotic Systems 6, no. 3 (January 1, 2009): 24. http://dx.doi.org/10.5772/7229.
Full textAbstract:
This paper presents a novel two-step autonomous navigation method for search and rescue robot. The algorithm based on the vision is proposed for terrain identification to give a prediction of the safest path with the support vector regression machine (SVRM) trained off-line with the texture feature and color features. And correction algorithm of the prediction based the vibration information is developed during the robot traveling, using the judgment function given in the paper. The region with fault prediction will be corrected with the real traversability value and be used to update the SVRM. The experiment demonstrates that this method could help the robot to find the optimal path and be protected from the trap brought from the error between prediction and the real environment.
8
García-Botella, Angel, Lun Jiang, and Roland Winston. "Flowline Optical Simulation to Refractive/Reflective 3D Systems: Optical Path Length Correction." Photonics 6, no. 4 (September 28, 2019): 101. http://dx.doi.org/10.3390/photonics6040101.
Full textAbstract:
Nonimaging optics is focused on the study of techniques to design optical systems for the purpose of energy transfer instead of image forming. The flowline optical design method, based on the definition of the geometrical flux vector J, is one of these techniques. The main advantage of the flowline method is its capability to visualize and estimate how radiant energy is transferred by the optical systems using the concepts of vector field theory, such as field line or flux tube, which overcomes traditional raytrace methods. The main objective this paper is to extend the flowline method to analyze and design real 3D concentration and illumination systems by the development of new simulation techniques. In this paper, analyzed real 3D refractive and reflective systems using the flowline vector potential method. A new constant term of optical path length is introduced, similar and comparable to the gauge invariant, which produces a correction to enable the agreement between raytrace- and flowline-based computations. This new optical simulation methodology provides traditional raytrace results, such as irradiance maps, but opens new perspectives to obtaining higher precision with lower computation time. It can also provide new information for the vector field maps of 3D refractive/reflective systems.
9
Min, J. E., S. K. Lee, and J. H. Ryu. "ADVANCED SURFACE-REFLECTED RADIANCE CORRECTION FOR AIRBORNE HYPERSPECTRAL IMAGERY IN COASTAL RED TIDE DETECTION." ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences V-3-2021 (June 17, 2021): 73–80. http://dx.doi.org/10.5194/isprs-annals-v-3-2021-73-2021.
Full textAbstract:
Abstract. Red tides are among the most common coastal hazards, causing serious damage to the coastal environment. Many satellite sensors can detect red tide blooms, but are limited in their detection of the exact area of the bloom and biological abundance in terms of spatial and spectral resolution. The high spatial and spectral resolutions of hyperspectral airborne remote sensing data may help overcome these limitations to analyze red tide blooms more effectively. To identify potential applications of hyperspectral airborne data in red tide detection, an integrated field campaign was performed in September 2016 off the coast of Tongyeong, South Korea. An AisaEAGLE sensor was installed on a Cessna 208B crewed aircraft to obtain hyperspectral images of an 18 km × 18 km coastal area. To assess the atmospheric correction of the hyperspectral data, in situ optical data and water samples were measured on two vessels concurrent with the flight path. Advanced surface-reflected radiance (Lr) correction and basic atmospheric path radiance (La) correction were performed on the hyperspectral images. Of these, Lr correction comprised a large proportion of the atmospheric correction. The atmosphere-corrected remote sensing reflectance data of the hyperspectral images closely matched the in-situ measurements. The data were assessed for red tide events using ratio analysis and the fluorescence line height technique; the ratio analysis more effectively detected regions with suspected red tides.
10
Surmick, David M., and Christian G. Parigger. "Tracking Temporal Development of Optical Thickness of Hydrogen Alpha Spectral Radiation in a Laser-Induced Plasma." Atoms 7, no. 4 (November 4, 2019): 101. http://dx.doi.org/10.3390/atoms7040101.
Full textAbstract:
In this paper, we consider the temporal development of the optical density of the H α spectral line in a hydrogen laser-induced plasma. This is achieved by using the so-called duplication method in which the spectral line is re-imaged onto itself and the ratio of the spectral line with it duplication is taken to its measurement without the duplication. We asses the temporal development of the self-absorption of the H α line by tracking the decay of duplication ratio from its ideal value of 2. We show that when 20% loss is considered along the duplication optical path length, the ratio is 1.8 and decays to a value of 1.25 indicating an optically thin plasma grows in optical density to an optical depth of 1.16 by 400 ns in the plasma decay for plasma initiation conditions using Nd:YAG laser radiation at 120 mJ per pulse in a 1.11 × 10 5 Pa hydrogen/nitrogen gas mixture environment. We also go on to correct the H α line profiles for the self-absorption impact using two methods. We show that a method in which the optical depth is directly calculated from the duplication ratio is equivalent to standard methods of self-absorption correction when only relative corrections to spectral emissions are needed.
Dissertations / Theses on the topic "On-line path correction"
1
Ržonca, Michal. "On-line korekce dráhy robotu na základě dat ze snímače vzdálenosti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443251.
Full textAbstract:
The main aim of this master’s thesis is to provide online path correction of 6 – axis robot leaded by an external distance measuring sensor interface. First part is describing the actual state and required options of some robot manufacturers. Next part justifies selection and is describing the real robotic cell. Third part is focused on programming of path correction of Kuka KR16 based on generated signal and also based on signal from distance sensor interface. There is also described the communication between PLC and robot and how to display data from robot to HMI. Last part is focused on data analysis and is describing some problems discovered by application of path correction.
Book chapters on the topic "On-line path correction"
1
Roychoudhuri, Lopamudra, and Ehab S. Al-Shaer. "Autonomic QoS Optimization of Real-Time Internet Audio Using Loss Prediction and Stochastic Control." In Technological Innovations in Adaptive and Dependable Systems, 239–60. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0255-7.ch015.
Full textAbstract:
Quality of Internet audio is highly sensitive to packet loss caused by congestion in links. Packet loss for audio is normally rectified by adding redundancy using Forward Error Correction (FEC). Alternatively, path diversity mechanisms are used to improve reliability and thus session quality. To achieve optimized receiver audio quality for transmissions using single or multiple paths, the authors propose a self-adaptive joint Error and Rate Control framework based on packet loss prediction and on-line quality assessment. The Error Control chooses appropriate FEC proactively to preserve quality with optimal bandwidth, using a Markov Decision Process (MDP) and a stochastic inventory control, a novel approach for multimedia error recovery. The Rate Control uses a quality optimization model to determine the optimal dispersion over single or multiple paths. This paper will present results using simulation and Internet experiments to show the superiority of this mechanism over other similar techniques.
Conference papers on the topic "On-line path correction"
1
Chun, Sejong. "Calculation of the Flow Profile Correction Factor Based on Flow Velocity Distribution Functions for Ultrasonic Flow Metering." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-4679.
Full textAbstract:
Abstract Transit-time ultrasonic flow metering relies on the flow profile correction factor (FPCF) to improve its measurement capability by converting line-integrated flow velocity into area-integrated flow velocity. It is because the flow velocity is integrated along ultrasonic paths between ultrasonic sensors by sending and receiving pulse signals in the transit-time ultrasonic flow metering. ISO 12242 (liquid flow metering) and ISO 17089 (gas flow metering) specify how to define the FPCF with a transit-time multi-path ultrasonic flow meter. The FPCF is applied to an averaged value of line-integrated flow velocities, not to each line-integrated flow velocity, according to the ISO standards. The present use of FPCF is validated in the fully-developed turbulent pipe flow, which a long straight pipe is installed upstream of the ultrasonic flow meter. However, the present FPCF would not be very accurate in asymmetric pipe flows with various conduit elements, such as elbows. This study attempts to apply the FPCF to each line-integrated flow velocity in transit-time multi-path ultrasonic flow metering. The FPCF can be applied to each line-integrated flow velocity if the FPCF is based on flow velocity distribution functions, such as those suggested by Salami (1984). The Salami’s flow velocity distribution functions include one symmetric flow, three one-peak flows, and two two-peak flows. The FPCF is calculated by line-integrals along the ultrasonic paths on each flow velocity distribution function. This study is the first attempt to show that the FPCF can be applied to convert the line-integrated flow velocities into the area-integrated flow velocity along each ultrasonic path.
2
Yang, Xuesen, Xiaofeng Guo, and Wei Dong. "On-Line Component Map Adaptive Procedure Based on Sensor Data." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16242.
Full textAbstract:
Abstract A key challenge in the gas turbine community is to adapt the engine model by matching measured data with simulation data. This study presents a procedure aiming to calibrate a certain type of gas turbine for power generation. To reproduce degradation, disturbance is injected into the healthy components maps at different time. Subsequently, six correction factors along with measured data and unmeasured parameters are coupled together using cooperative working equations and optimized based on primal-dual interior point method. When performing the adaptive procedure, Jacobian and hessian matrices are calculated using finite difference since the component maps have external, mapped, functions implemented as lookup-tables, and mode-switching statements. To improve the accuracy of first-order and second-order partial derivatives, the finite difference is enhanced by Richardson extrapolation method. The search scope of correction factors and unmeasured parameters are determined by the whole working conditions. Meanwhile, an adaptive update method of initial solution is proposed to make sure the convergence of the optimization procedure as quickly as possible. Finally, the proposed method is further applied to the on-line adaptation in case of performance degradation. The influence of measurement noise on optimization is also studied. It is demonstrated that the procedure is capable of refining the component maps progressively, which is significant for the model-based gas path diagnostics and prognostics.
3
Sasongko, R. A., and J. Sembiring. "Development of Flight Guidance System of a Small Unmanned Aerial Vehicle (UAV)." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48561.
Full textAbstract:
This paper presents the development of a guidance system for a small Unmanned Aerial Vehicle (UAV) system which combines a waypoints following and an obstacle avoidance systems so that the UAV has a capability to operate in an environment whose ground condition is not completely known. The waypoints following system works by adopting the VOR-Hold approach, in which a correction command will be produced to reduce the angle difference between the desired path and the line connecting the actual UAV position and the subsequent destination point. An avoidance algorithm is developed and integrated with the path following system. In case of the UAV faces an obstacle lying on its flight path, then the avoidance system will generate a set of new waypoints for correcting the flight path, so that the UAV can avoid the obstacle and then returns to the previous flight path. The proposed avoidance approach bases its algorithm on the utilization of ellipsoid geometry for defining a restricted zone containing the obstacle, which is assumed to be already identified by the detection system. When the restricted ellipsoid zone has already been established, the algorithm then computes the locations of new waypoints on the edge of the ellipsoid. The algorithm then is simulated and evaluated in some cases representing situations when an UAV has to avoid obstacles during its flight to a predefined destination.
4
Ahmad, Rafiq, and Peter Plapper. "Safe and Automated Tool-Path Generation for Multi-Axis Production Machines." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36742.
Full textAbstract:
Multi-axis machines are growing rapidly their precision and complexity with the increasing importance of machine intelligence, automation, optimization and safety. It is necessary to identify collision risks and avoid them in manufacturing otherwise production stops may cost a huge amount to the manufacturing company. This study has focused on safe trajectory generation for CNC machines especially focusing on high risked non-functional trajectories. These machines should be able to see any unwilling situation (i.e. collisions) in their vicinity and must be able to detect and react automatically in real-time for safe tool movements. Currently CAM software and some multi-axis machines are able to detect collisions but they do not have any solution to avoid such collisions automatically. The main objective is to make multi-axis machine vision system effective enough that it can see all its activities regarding collisions and can react or command automatically online as well as off-line for real and virtual productions. In presence of obstacles during manufacturing, the proposed approach will provide decisions regarding trajectory correction and improvement automatically. The proposed vision concept is able to take into account the evolution of the scene i.e. the aspects of changes to the obstacle like shape, size or presence during production. The application presented in this paper is for 2D traversal safe online trajectories generation in virtual simulated dynamic environment, which will be adapted to the real-time real machining scenarios at shop-floor by integrating it with STEP-NC technology in future.
5
Roumeliotis, I., N. Aretakis, and A. Alexiou. "Industrial Gas Turbine Health and Performance Assessment With Field Data." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57722.
Full textAbstract:
The paper presents a thorough analysis of historical data and results acquired over a period of two years through an online real-time monitoring system installed at a Combined Heat and Power (CHP) plant. For gas turbine health and performance assessment, a Gas Path Analysis tool based on the adaptive modeling method is integrated into the system. An engine adapted model built through a semi-automated method is part of a procedure which includes a steam/water cycle simulation module and an economic module used for power plant performance and economic assessment. The adaptive modeling diagnostic method allowed for accurate health assessment during base and part load operation identifying and quantifying compressor recoverable deterioration and the root cause of an engine performance shift. Next the performance and economic assessment procedure was applied for quantifying the economic benefit accrued by implementing daily on-line washing and for evaluating the financial gains if the off-line washings time intervals are optimized based on actual engine performance deterioration rates. The results demonstrate that this approach allows continuous health and performance monitoring at full and part load operation enhancing decision making capabilities and adding to the information that can be acquired through traditional analysis methods based on heat balance and base load correction curves.
6
Narain, Jaya, and Amos G. Winter. "A Hybrid Computational and Analytical Model of Inline Drip Emitters." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85871.
Full textAbstract:
This paper details a hybrid computational and analytical model to predict the performance of inline pressure-compensating (PC) drip irrigation emitters. The term inline refers to flow control devices mounted within the irrigation tubing. Pressure-compensating emitters deliver a relatively constant flow rate over a range applied pressure to accurately meter water to crops. Flow rate is controlled within the emitter by directing the water through a tortuous path (which imposes a fixed resistance), and then through a variable resistor composed of a flexible membrane that deflects under changes in pressure, restricting the flow path. An experimentally validated computational fluid dynamics (CFD) model was used to predict flow behavior through tortuous paths, and a pressure resistance parameter was derived to represent the pressure drop with a single variable. The bending and shearing mechanics of the membrane were modeled analytically and refined for accuracy by deriving a correction factor using finite element analysis. A least-squares matrix formulation that calculates the force applied by a line load of any shape, along which there is a prescribed deflection applied on a rectangular membrane, was derived and was found to be accurate to within one percent. The applicability of the assumption of locally fully developed flow through the pressure compensating chamber in a drip emitter was analyzed. The combined hybrid computational-analytical model reduces the computational time of modeling drip emitter performance from days to less than 30 minutes, dramatically lowering the time required to iterate and select optimal designs. The model was validated using three commercially available drip emitters, rated at 1.1, 2, and 3.8 L/hr. For each, the model predicted the flow rate with an error of twenty percent or less, as compared to the emitter performance published by the manufacturer.
7
Ryberg, A., M. Ericsson, A. K. Christiansson, K. Eriksson, J. Nilsson, and M. Larsson. "Stereo vision for path correction in off-line programmed robot welding." In 2010 IEEE International Conference on Industrial Technology. IEEE, 2010. http://dx.doi.org/10.1109/icit.2010.5472442.
Full text
8
Tyapin, Ilya, Knut Berg Kaldestad, and Geir Hovland. "Off-line path correction of robotic face milling using static tool force and robot stiffness." In 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). IEEE, 2015. http://dx.doi.org/10.1109/iros.2015.7354157.
Full text
9
Lee, B. J., May-Fun Liou, and Meng-Sing Liou. "Conceptual Aerodynamic Design of a Tail-Cone Thruster System Under Axi-Symmetric Inlet Distortion." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75861.
Full textAbstract:
This paper presents a conceptual design of a tail-cone thruster system which is operating under an axisymmetric inlet distortion. An effort to realize the targeted fuel burn saving that was proposed in NASA’s STARC_ABL aircraft design is made through a CFD based design approach. This method employs three iterative steps to exploit the CFD tools until the design requirements are met: a quasi-2D through-flow model to design the fan/EGV, a 3-D RANS simulation of the single blade row to account for the inlet/fan and the EGV/nozzle interaction, and a 3-D RANS simulation of the airframe with a propulsor installed – propulsion airframe integration (PAI). The design requirements which include the thrust, and shaft power of the propulsor are matched throughout the evaluations coming from two CFD domains, i.e., the turbo-machinery and the PAI. During the switch between these different computational domains, the inlet and exit profiles are matched via the correction factors of the body-force model. The present tail-cone thruster (TCT) aerodynamic design leverages a low-pressure ratio fan (FPR = 1.2∼1.25) of which the camber-line angles are predicted by a quasi-2D through-flow model. The quasi-2D model is derived to analyze the radially distorted flow resulting from the ingested boundary layer at the inlet. It also estimates the appropriate velocity vectors of the metal angles of the fan and EGV which is subjected to different types of vortex at the fan exit. The baseline geometry is revisited and its internal flow-path and exhaust cone are redesigned to illustrate the strong correlation among the components of the propulsor in the PAI domain. The peak efficiency point of the fan/EGV with respect to the blade counts, a.k.a. solidity, and rotational speed is chosen for the cruise condition via parametric studies. The corresponding performance maps are presented. The resulting performance metrics of the new conceptual design of the BLI propulsor are analyzed and compared with these of the baseline in the PAI aspect. Finally, ideas of the CFD based design of a BLI propulsor are discussed based on the observations drawn from the numerical results.
10
Berkovich, Y., S. Glickman, L. Levin, U. Eitan, and A. Gordinsky. "On-LineTurbine Internal Efficiency Monitoring for Steam Turbine Condition Diagnostics." In ASME 2006 Power Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/power2006-88080.
Full textAbstract:
The integral diagnostics factor used for the evaluation of turbine island condition is the turbine heat rate corrected to constant steam parameters and condenser pressure which is called “corrected turbine heat rate”. In case of excessive deviation of corrected heat rate from its normal value, it is necessary to implement a diagnostic subsystem for determining the source of the deviation. The following subsystems of the turbine island have to be taken into consideration: turbine steam path, turbine end seals, control valves, etc. For each subsystem it is necessary to select the calculated or measured parameter(s), which will be used as diagnostic factors for turbine condition evaluation purposes. For the turbine steam path subsystemthe internal efficiency of the high pressure turbine (HP) and intermediate turbine (IP) can be used. Selection of the internal efficiency as diagnostics factor is based on its high sensitivity to variations in steam path conditions (erosion, steam path fouling and so on), as well as to steam path diaphragm and radial sealing conditions. However, the basic internal efficiency calculation results of HP and IP turbines at different loads, using measured parameters, show very high sensitivity of the calculation results to random measurement errors, random components of the regulation process and variations in spatial and time distribution of the temperature and pressure fields. This high sensitivity causes the uncertainty of the calculation results to approach ± 1.5 % and means that the results can not be used for diagnostic purposes. To achieve acceptable results for uncertainty (± 0.3 %) special methods of mathematical analysis need to be applied, including robust estimation, precise multivariate approximation, filtration and others. Furthermore, the HP turbine internal efficiency depends on control valve position and thus can not be directly used as a diagnostic factor in an on-line turbine diagnostic system. To solve this problem, special methods were developed for correcting the real efficiency value to the valve wide open position. The developed method was verified by a set of specially designed tests and results have shown that this technique can be applied for on-line calculations. The described system for on-line turbine internal efficiency monitoring was developed in cooperation between IEC and Berman Engineering Ltd. The system was implemented on a 550 MW unit and has been in operation for two years. The results of operation show that the system yields the required expanded uncertainty in the range of ± 0.3 %. The system is characterized by high reliability and a friendly interface.