A Hybrid Simulation Model to Predict the Steady-State Thermal Profile of Hermetic Reciprocating Compressors
Thermal management, hermetic reciprocating compressors, finite element method
Numerical simulation models are paramount to design compressors that follow reliability and efficiency requirements. This paper presents a simulation model to predict the steady-state thermal profile of hermetic reciprocating compressors. A finite element method is used to compute the temperature distribution of the solid components and the fluid in the suction and discharge lines, whereas a lumped-parameter formulation is used to evaluate the internal environment temperature and the gas temperature at the end of the compression cycle. The heat transfer between the gas and the solid components is predicted using imposed convective heat transfer coefficients; some of which are estimated using heat transfer correlations, and others calibrated using experimental data and a genetic optimization algorithm. The numerical results were validated by comparisons with experimental data for different operating conditions and rotation speeds, showing that the model can be used to predict the compressor thermal profile in the entire application envelope. The low computational cost of the model enables its application to carry out sensitivity analysis and to assess thermal management alternatives to improve the compressor reliability or thermodynamic performance.