Influence of the Heat Transfer on the Pressure Field in Radial Diffusers Flows

The radial diffuser geometry has been largely used to analyze the flow through refrigeration compressor valves. The majority of the researchers have modeled the flow as isothermal. In fact, the valve system is heated during the compression process and the refrigerant gas flows through heated channels. In this work, the flow through the radial diffuser is model as non-isothermal in order to verify the influence of the heat transfer process on the pressure field on the frontal disk, which is an important result for simulating the behavior of the valve. The Finite Volume Method is used for discretizing the governing equations. The SIMPLEC-Semi-Implicit Method for Pressure-Linked Equations Consistent algorithm applied to a staggered mesh is used for solving the pressure-velocity coupling problem. The power-law scheme is employed as interpolation function for the convective-diffusive terms, and the algebraic equations systems are solved by the TDMA-Three Diagonal Matrix Algorithm. The flow behavior is analyzed for Reynolds number varying from 500 to 2000, dimensionless gap between the frontal (valve reed) and back (valve seat) disks ranging from 0.04 to 0.1, and three heat transfer configurations. The numerical results have shown that the overall pressure drop through the flow can be 21% higher when the heat transfer process is included in the flow modeling.