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Cesar J. Deschamps - One of the best experts on this subject based on the ideXlab platform.
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A simulation approach for hermetic Reciprocating Compressors including electrical motor modeling
International Journal of Refrigeration, 2015Co-Authors: Thiago Dutra, Cesar J. DeschampsAbstract:The design of a high-efficiency Reciprocating compressor requires an understanding of the interactions between different phenomena occurring inside the compressor. This paper describes a comprehensive simulation approach for hermetic Reciprocating Compressors including modeling of the electrical motor. The simulation of the compression cycle follows an integral control volume formulation for mass and energy conservation. A thermal model is adopted with steady-state thermal energy balances applied to the compressor components via global thermal conductances. The equivalent circuit method is employed to form a steady-state model of a single-phase induction motor. The coupling between the three models provides the motor slip and mean compressor speed, which are seen to affect the compressor efficiency. The simulation model is validated through comparisons between predictions and measurements of the parameters associated with the compressor efficiency, temperature distribution and motor performance. A parametric analysis is carried out to investigate the dependence of the motor temperature on the input voltage and the results are discussed.
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A Simplified CFD Model for Simulation of the Suction Process Of Reciprocating Compressors
2013Co-Authors: Evandro L L Pereira, Cesar J. Deschamps, Claudio J. Santos, Rodrigo KremerAbstract:The suction process in Reciprocating Compressors is strongly affected by the valve dynamics and the pulsating flow throughout the suction muffler. This paper describes a simplified computational fluid dynamics (CFD) model to simulate the flow through the muffler, suction valve and a small region inside the cylinder. The proposed method is applied to predict the suction process of a small Reciprocating compressor and its adequacy is compared with a more time elaborate model in terms of accuracy, computation cost and usability.
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Development of an In-Cylinder Heat Transfer Correlation for Reciprocating Compressors
2013Co-Authors: Fernanda P. Disconzi, Cesar J. Deschamps, Evandro L L PereiraAbstract:The gas superheating that takes place throughout the suction system and inside the cylinder of Reciprocating Compressors adversely affects their overall efficiency. Simulation models adopted in the design of Reciprocating Compressors are generally based on lumped formulation and rely on empirical correlations for different physical phenomena, including the gas-to-wall heat transfer in the cylinder. The present paper reports a numerical study of heat transfer inside the cylinder of a simplified geometry of Reciprocating compressor, considering the effect of fluid flow through the valves. Predictions for the instantaneous heat transfer at the walls are obtained for actual operating conditions and compared with estimates given by correlations commonly adopted for Reciprocating Compressors. It is shown that the increase of heat transfer during the suction and discharge processes is not properly accounted for by such correlations. Based on the predictions, a new correlation for the in-cylinder heat transfer is put forward and tested in different operating conditions.
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a heat transfer model combining differential and integral formulations for thermal analysis of Reciprocating Compressors
2012Co-Authors: Joel Sanvezzo, Cesar J. DeschampsAbstract:Heat transfer in hermetic Compressors is a complex phenomenon strongly affected by fluid flow inside and outside the compression chamber and by the efficiency of both the electrical motor and the crankshaft mechanism. This paper presents a heat transfer model for thermal analysis of Reciprocating Compressors formed by combining a lumped formulation for convective heat transfer in some selected regions and a three-dimensional differential formulation for heat conduction in the solid components. Convective heat transfer coefficients were evaluated from correlations available in the literature so as to avoid calibration based on experimental data. The model was applied to a Reciprocating compressor operating in a fully periodic condition and predictions for temperature distribution, heat transfer and volumetric efficiency were seen to be in reasonable agreement with measurements.
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influence of piston on effective areas of reed type valves of small Reciprocating Compressors
Hvac&r Research, 2011Co-Authors: Evandro L L Pereira, Cesar J. DeschampsAbstract:Most simulation models for Reciprocating Compressors adopt the concept of effective force and flow areas to characterize the valve dynamics and the mass flow rate through the valve. However, in the discharge process, the proximity between the piston and the cylinder head may have a significant impact on the flow field and, hence, should be taken into account in the evaluation of both effective areas. For instance, there is an additional viscous friction loss associated with the radial flow through the very narrow clearance left in the cylinder when the piston is close to the top dead center. In addition, the flow exiting the clearance may even affect the size of recirculating flow regions in the discharge port and on the valve seat. In the present study, a computational fluid dynamics model is employed to analyze the influence of the piston on the effective flow and force areas of a discharge valve of simplified geometry. Based on the results, a method is then proposed to evaluate the effective flow and f...
A Oliva - One of the best experts on this subject based on the ideXlab platform.
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Advanced Numerical Simulation Model of Hermetic Reciprocating Compressors
2011Co-Authors: Joaquim Rigola, CARLOS DAVID PÉREZ SEGARRA, A OlivaAbstract:A complete and advanced numerical simulation model of the thermal and fluid-dynamic performance of hermetic Reciprocating Compressors has been developed and is used in the optimization Electrolux compressor design. During the last few years several global experimental validations have been carried out. A detailed instrumentation of a commercial Reciprocating compressor for household refrigerators has been developed to determine the average temperature distribution on the surface and the gas at different strategic points in all the compressor zones. This work is focussed on presenting a parametric study of a concrete commercial hermetic Reciprocating compressor by means of the numerical simulation model, together with a detailed experimental comparison. The objective is to demonstrate how both global and detailed experimental comparison confirms the possibilities offered by these models.
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detailed thermodynamic characterization of hermetic Reciprocating Compressors
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: C D Perezsegarra, Joaquim Rigola, M Soria, A OlivaAbstract:Abstract The aim of this paper is the detailed analysis of different well-known thermodynamic efficiencies usually used to characterize hermetic Compressors. Attention is focussed on the volumetric efficiency, the isentropic efficiency, and the combined mechanical–electrical efficiency. A procedure is presented to detach these efficiencies into their main components (physical sub-processes) to get deeper insight on the overall behavior. The volumetric efficiency is split into partial efficiencies related to pressure drop and heat transfer effects, supercharging effects, superdischarging effects, leakages, etc. The isentropic efficiency is detached using two different points of view: the work associated to the individual sub-processes (compression, discharge, expansion, suction), and the work associated to the underpressures, overpressures, and between the inlet and outlet mean compressor pressures. Finally, the combined mechanical–electrical efficiency is related to the heat transfer losses/gains, and to the exergy transfers and exergy destroyed. Even though some of the concepts introduced in the paper can be applied to different kinds of Compressors, the discussion is specially focussed on hermetic Reciprocating Compressors. An advanced simulation model developed by the authors has been used to generate data to illustrate the possibilities of the detailed thermodynamic characterization proposed. The criteria developed are useful tools for comparison purposes, to characterize Compressors, and to assist designers during the optimization process.
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detailed experimental validation of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors
Hvac&r Research, 2004Co-Authors: Joaquim Rigola, G Raush, C D Perezsegarra, A OlivaAbstract:A detailed experimental analysis of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors is presented. A hermetic compressor for household appliances has been experimentally tested. The fluid and solid thermal map evolution has been logged in several strategic points. The absolute instantaneous pressure has been determined in three specific zones: suction muffler, compression chamber, and cylinder head. The pV diagram inside the compressor chamber has also been experimentally obtained for the different working conditions studied without any previous hypothesis to determine the absolute pressure level. A complete description of the experimental equipment and its instrumentation is included. This experimental approach has allowed validating a mathematical model developed for the numerical simulation of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors. Good agreement between the detailed numerical results and the experimental data has been obtained, allowin...
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modeling and numerical simulation of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors part 2 experimental investigation
Hvac&r Research, 2003Co-Authors: Joaquim Rigola, C D Perezsegarra, A OlivaAbstract:An experimental validation of a mathematical model developed for the numerical simulation of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors is presented. Details of the physical model and a critical analysis of the quality of the numerical solutions are presented in a companion paper (Part 1). Different compressor geometries have been tested considering a wide range of working conditions and refrigerant fluids. A complete description of the experimental equipment and its instrumentation is included here. Good agreement between numerical and experimental data has been obtained, generating a better understanding of the thermal and fluid dynamic behavior of these Compressors.
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modeling and numerical simulation of the thermal and fluid dynamic behavior of hermetic Reciprocating Compressors part 1 theoretical basis
Hvac&r Research, 2003Co-Authors: C D Perezsegarra, Joaquim Rigola, A OlivaAbstract:A detailed numerical simulation of the thermal and fluid dynamic behavior of Reciprocating Compressors, commonly used in household refrigerators and freezers, has been developed. The model is based on the integration of the transient fluid conservation equations (continuity, momentum, and energy) in the whole compressor domain (compression chamber, valves, manifolds, mufflers, shell, piston, connecting tubes, parallel paths, etc.) using instantaneous local mean values for different variables. Effective flow areas are evaluated considering a multidimensional model based on modal analysis of fluid interaction in the valve. In order to evaluate the instantaneous compression chamber volume, force balances in the crankshaft connecting rod mechanical system are simultaneously solved at each time-step. The thermal analysis of the solid elements is based on global energy balances at each macro-volume considered (shell, muffler, tubes, cylinder head, crankcase, motor, etc.). The resulting governing equations (flui...
Joaquim Rigola - One of the best experts on this subject based on the ideXlab platform.
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object oriented simulation of Reciprocating Compressors numerical verification and experimental comparison
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: R Damle, Joaquim Rigola, C D Perezsegarra, J Castro, Assensi OlivaAbstract:Numerical simulation of Reciprocating Compressors is important for the design, development, improvement and optimization of the elements constituting the compressor circuit. In this work, an object-oriented unstructured modular numerical simulation of Reciprocating Compressors is presented. Pressure correction approach is applied for the resolution of tubes, chambers and compression chambers, while valve dynamics are modelled assuming a spring-mass system having single degree of freedom. The modular approach offers advantages of handling complex circuitry (e.g. parallel paths, multiple compressor chambers, etc.), coupling different simulation models for each element and adaptability to different configurations without changing the program. The code has been verified with some basic tests for assuring asymptotic behaviour to guarantee error free code and physically realistic results. Cases with different compressor configurations and working fluids (R134a, R600a and R744) have also been worked out. Numerical results are compared with experimental data and illustrative cases of multi-stage compression are also presented.
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Numerical Study and Experimental Comparison of CO2 Reciprocating Compressors for Small Cooling and/or Freezing Capacity Applications
2011Co-Authors: Joaquim Rigola, CARLOS DAVID PÉREZ SEGARRA, G Raush, Assensi OlivaAbstract:The present paper is a numerical and experimental comparative study of hermetic and semi-hermetic Reciprocating Compressors working with carbon dioxide as fluid refrigerant against the conventional R134a hermetic Compressors. When cooling conditions for one-stage compressor type (i.e., evaporation temperatures between 7.2oC and –10oC) have been considered, the numerical and experimental results obtained have shown a reasonable good agreement, while the comparative global values have indicated very similar efficiencies between the carbon dioxide compressor and the conventional ones. In all these cases the CO2 semi-hermetic compressor presents higher mass flow rate and better efficiency than the CO2 hermetic compressor. However, when freezing conditions are analysed (i.e., evaporation temperature between –10oC and –40oC) the onestage CO2 compressor shows lower COPs in comparison with R134a conventional compressor. In these cases a numerical study of the availability of two-stage semi-hermetic Reciprocating Compressors is presented in order to obtain comparative or even better efficiencies against conventional hermetic Reciprocating Compressors.
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Advanced Numerical Simulation Model of Hermetic Reciprocating Compressors
2011Co-Authors: Joaquim Rigola, CARLOS DAVID PÉREZ SEGARRA, A OlivaAbstract:A complete and advanced numerical simulation model of the thermal and fluid-dynamic performance of hermetic Reciprocating Compressors has been developed and is used in the optimization Electrolux compressor design. During the last few years several global experimental validations have been carried out. A detailed instrumentation of a commercial Reciprocating compressor for household refrigerators has been developed to determine the average temperature distribution on the surface and the gas at different strategic points in all the compressor zones. This work is focussed on presenting a parametric study of a concrete commercial hermetic Reciprocating compressor by means of the numerical simulation model, together with a detailed experimental comparison. The objective is to demonstrate how both global and detailed experimental comparison confirms the possibilities offered by these models.
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detailed thermodynamic characterization of hermetic Reciprocating Compressors
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: C D Perezsegarra, Joaquim Rigola, M Soria, A OlivaAbstract:Abstract The aim of this paper is the detailed analysis of different well-known thermodynamic efficiencies usually used to characterize hermetic Compressors. Attention is focussed on the volumetric efficiency, the isentropic efficiency, and the combined mechanical–electrical efficiency. A procedure is presented to detach these efficiencies into their main components (physical sub-processes) to get deeper insight on the overall behavior. The volumetric efficiency is split into partial efficiencies related to pressure drop and heat transfer effects, supercharging effects, superdischarging effects, leakages, etc. The isentropic efficiency is detached using two different points of view: the work associated to the individual sub-processes (compression, discharge, expansion, suction), and the work associated to the underpressures, overpressures, and between the inlet and outlet mean compressor pressures. Finally, the combined mechanical–electrical efficiency is related to the heat transfer losses/gains, and to the exergy transfers and exergy destroyed. Even though some of the concepts introduced in the paper can be applied to different kinds of Compressors, the discussion is specially focussed on hermetic Reciprocating Compressors. An advanced simulation model developed by the authors has been used to generate data to illustrate the possibilities of the detailed thermodynamic characterization proposed. The criteria developed are useful tools for comparison purposes, to characterize Compressors, and to assist designers during the optimization process.
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Parametric studies on hermetic Reciprocating Compressors
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: Joaquim Rigola, CARLOS DAVID PÉREZ SEGARRA, Assensi OlivaAbstract:An advanced numerical simulation model for the thermal and fluid dynamic optimization of hermetic Reciprocating Compressors has been developed. The quality of the numerical solution has been verified by means of a critical analysis of the different sources of errors, and validated through an extensive experimental comparison. This work is focused on presenting different parametric studies of hermetic Reciprocating Compressors, based on the numerical simulation model developed. Results presented show the influence of different aspects (geometry, motor, valves, working conditions, etc.) on the basis of the meaningful non-dimensional parameters, which describe the compressor behaviour (volumetric and isentropic efficiency, coefficient of performance, etc.). The idea of this paper is to show the possibilities offered by the simulation model and its final objective, a better understanding of the thermal and fluid dynamic compressor behaviour to improve the design of these equipments.
Ian Bennett - One of the best experts on this subject based on the ideXlab platform.
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valve failure prognostics in Reciprocating Compressors utilizing temperature measurements pca based data fusion and probabilistic algorithms
IEEE Transactions on Industrial Electronics, 2020Co-Authors: T H Loutas, Nick Eleftheroglou, George Georgoulas, Panagiotis Loukopoulos, Ian BennettAbstract:In this paper, temperature measurements are utilized to develop health indicators based on principal component analysis toward the probabilistic estimation of the remaining useful life (RUL) of Reciprocating Compressors in service. Temperature degradation histories obtained from 13 actual valve failure cases constitute the training data in a data-driven prognostic approach. Two data-driven prognostic methodologies are presented and proposed based on probabilistic mathematical models, i.e., gradient boosted trees and nonhomogeneous hidden semi-Markov models. The training and testing process of all models is described in detail. RUL prognostics in unseen data are obtained for all models. Beyond the mean estimates of the RUL, the uncertainty associated with the point prediction is quantified and upper/lower confidence bounds are also estimated. Prediction estimates for 12 real-life failure cases are presented and the pros and cons of each model's performance are highlighted. Several metrics are utilized to assess the performance of the prognostic algorithms and conclusions are drawn regarding the prognostic capabilities of each of them.
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Combining Canonical Variate Analysis, Probability Approach and Support Vector Regression for Failure Time Prediction
2017 International Conference on Sensing Diagnostics Prognostics and Control (SDPC), 2017Co-Authors: Xiaochuan Li, Fang Duan, David, Ian BennettAbstract:Reciprocating Compressors are widely used in oil and gas industry for gas transport, lift and injection. Critical Reciprocating Compressors that operate under high-speed conditions, flow hazardous gases and have a high duty cycle are target rotating equipment on maintenance improvement lists due to downtime risks and safety hazards. Estimating performance deterioration and failure time for Reciprocating Compressors could potentially reduce downtime and maintenance costs, and improve safety and availability. This study presents an application of Canonical Variate Analysis (CVA), Cox Proportional Hazard (CPHM) and Support Vector Regression (SVR) models to estimate failure degradation and remaining useful life based on sensory data acquired from an operational industrial Reciprocating compressor. CVA was used to extract a one-dimensional health indicator from the multivariate data sets, thereby reducing the dimensionality of the original data matrix. The failure rate was obtained by using the CPHM based on historical failure times. Furthermore, a SVR model was used as a prognostic tool following training with failure rate vectors obtained from the CPHM and the one-dimensional performance measures obtained from the CVA model. The trained SVR model was then utilized to estimate the failure degradation rate and remaining useful life. The results indicate that the proposed method can be effectively used in real industrial processes to predict performance degradation and failure time.
E Navarro - One of the best experts on this subject based on the ideXlab platform.
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a phenomenological model for analyzing Reciprocating Compressors
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: E Navarro, Eric Granryd, Javier F Urchueguia, Jose M CorberanAbstract:A new model for hermetic Reciprocating Compressors is presented. This model is able to predict compressor efficiency and volumetric efficiency in terms of a certain number of parameters (10) representing the main sources of losses inside the compressor. The model provides users with helpful information about the way in which the compressor is designed and working. A statistical fitting procedure based on the Monte Carlo method was developed for its adjustment. The model can predict compressor performance at most points with a maximum deviation of 3%. A possible gas condensation on cold spots inside the cylinder during the last part of the compression stroke was also evaluated.
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performance analysis of a series of hermetic Reciprocating Compressors working with r290 propane and r407c
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: E Navarro, Javier F Urchueguia, Jose M Corberan, Eric GranrydAbstract:Abstract In this paper, a series of Compressors with different capacities and geometries working with propane as refrigerant are analyzed in terms of the compressor model developed by [E. Navarro, E. Granryd, J.F. Urchueguia, J.M. Corberan, A phenomenological model for analyzing Reciprocating Compressors, International Journal of Refrigeration, in this issue, doi:10.1016/j.irefrig.2007.02.006 ]. The relative influence of the diverse compressor losses is estimated as a function of the operating conditions. In addition, a comparison study between propane and R407C was carried out for one compressor and the observed differences were analyzed in terms of the compressor model. This study was also useful to verify the model's goodness with the aim of predicting the compressor performance with an untested refrigerant.
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test results of performance and oil circulation rate of commercial Reciprocating Compressors of different capacities working with propane r290 as refrigerant
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: E Navarro, Javier F Urchueguia, Jose Gonzalvez, Jose M CorberanAbstract:Abstract In this experimental investigation five R407C positive displacement hermetic Reciprocating Compressors, covering different capacities, displacement, stroke-to-bore ratios and number of cylinders, have been characterized using propane as refrigerant by means of a specifically designed characterization test rig. Test results have been systematically compared with their R407C reference performance data to obtain a complete picture on changes on the volumetric efficiency and compressor efficiency amongst others. The Compressors used POE oil as lubricant and additional oil circulation rate (OCR) tests at steady state conditions were done to evaluate possible effects and differences to the traditionally used mineral oils.
