We participated in this year’s International Conference on Screw Machines and had a really good time. From September 7th to 8th experts from academic research and industry gathered in Dortmund to present and discuss the latest developments in screw compressor technology. Rainer Andres and Jan Hesse from CFX Berlin presented the topic “Investigation of Radial Gap Size Change under Load and the Impact on Performance for a Twin Screw Compressor using Numerical Simulation”
This paper shows one workflow to adapt the deformation results of a structural simulation to a CFD setup. It starts with a CFD simulation (including CHT for the rotor and housing solids) with constant radial clearances using TwinMesh to realize the necessary mesh deformation inside the working chamber and Ansys CFX as the CFD solver. In a next step the temperature of the housing and the rotor solids and the pressure on the fluid sides are mapped on a structural mechanical setup solved by Ansys Mechanical. The change of the radial clearances depending on the deformation of the solids is used as an input for the final CFD simulation using an adapted mesh for the working chambers.
A simplified method to take the change of the radial clearance sizes along the rotor axis into account was shown. It can be used to see the impact on the machine behaviour in more detail and get more realistic results for the real operating condition.