Numerical investigation of the flow in scroll compressor: consideration of newly enforced refrigerant*

We numerically investigated the three-dimensional flow field in a scroll compressor with bypass valves under different pressure ratios (between inlet and discharge) of 2.1 and 3.4. Restricting the use of refrigerants with a GWP (global warming potential) above 750 for split air conditioners by EU regulations, it is required to analyze the variation caused by the alternative refrigerant. In the same context, we consider R454B and R452B, as alternative refrigerant of conventional R410A. We apply the SDM (structured dynamic mesh) to simulate the shape change due to the movement of the orbiting scroll. During the opening or closing of a valve, rapid fluctuations in velocity occur near the valve, and there is a pressure drop in the flank gap region. However, these local flow characteristics have little effect on the global pressure distribution within the chamber, resulting in a relatively uniform pressure distribution. Nonetheless, these local flows can affect the performance of the compressor and the functioning of lubricating oil during actual compressor operation. We will further discuss not only the performance differences of the compressor under each operating condition, but also on the local flow characteristics.