Supplementary data for: Investigations to reduce rarefied gap flows within positive displacement vacuum pumps by utilising surface structures

The data of the files contained here belong to the following figures of the related publication: Validation_gas_rarefaction: figures (7a) and (7c) Validation_sawtooth_angle: figures (7b) and (7d) ideal_sawtooth: figure (8) rounded_sawtooth: figure (9) movement_of_structure: figure (10) Abstract of related publication The ultimate pressure and efficiency of positive displacement vacuum pumps is limited by the backflow through the gaps within the machines.

These gap flows are typically reduced by decreasing the gap height, which is limited for reasons of operational safety. Therefore, this study concentrates on the reduction of rarefied gap flows by means of suitable surface structures whose dimensions are small compared to the gap height without simultaneously reducing the minimum gap height. For this purpose, a method is presented to efficiently calculate the impact of the surface structure on these gap flows.

Based on this method, design parameters for the choice of a suitable surface structure are discussed. Furthermore, a possible transfer for the application on the rotors is shown including a proposal for the machining process. Acknowledgement Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation).

Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) – Projektnummer 513663608. The authors gratefully acknowledge the computation time provided on the Linux HPC cluster at Technical University Dortmund (LiDO3), partially funded in the course of the Large-Scale Equipment Initiative by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) as project 271512359.