Investigation of Pressure Drop in Refrigerant Pipes of an Automotive Air Conditioning System

This paper presents an experimental and numerical investigation of the pressure drop of automotive refrigerant pipes. The measurement is done with a test rig that is able to set a defined one-or two-phase state at the inlet of an exchangeable test section. With the experimental data, CFD simulations are validated. There is a liquid and a hot gas line being investigated in this work. It turns out that transition pieces between pipe and hose elements have a significant influence on the pressure drop. Although the connection technology is the same, it must always be checked how the internal structure of this transition piece is designed and whether this has an influence on the pressure drop. It is also found that the compressibility of the gas, especially at low pressures and high mass flows, is a physical effect that cannot be neglected and must be implemented in the CFD simulation. All in all, CFD simulations are capable of reproducing the experimental data well after taking these findings into account