CFD analysis of transient flows in a linear compressor using a 1D-CFD coupled model

In refrigerant compressors, superheat is one of the main factors affecting compressor performance. To accurately predict superheat, a transient conjugate heat transfer model using a moving mesh should be used, but the computation time is too long to be practical. Therefore, 1-dimensional (1D) lumped model, which requires calibration with experimental data, has mainly been used for predicting temperature in the suction system. Recently, a coupled model combining a transient 1D lumped model and a steady state CFD model, which does not require experimental data, was developed. However, the coupled model had about 15% error when predicting the suction system temperatures of a linear compressor, since it only included the transient effects of the cylinder flow. Thus, in this paper, we developed a transient model that uses the temperature of solid parts in the coupled model's results as the wall boundary condition, to reduce computation time. In addition, momentum sources were used to describe the flow between the internal body and the compressor housing caused by internal body vibration. Using this transient model with the momentum sources, we predicted the suction system temperature to within about 5% error at maximum, significantly improving the accuracy of the previous coupled model.