Research on the flowrate and diaphragm movement in a diaphragm compressor for a hydrogen refueling station

•The influence of generatrix on the clearance volume and the diaphragm movement.•Same cavity volume does not mean the same flowrate for a diaphragm compressor.•Compressor flowrate and diaphragm radial stress have a conflicting association.•Diaphragm radial stress has a higher priority than compressor flowrate in design.

The diaphragm compressor flowrate and diaphragm radial stress are the two evaluation criteria of diaphragm compressors when applied in hydrogen refueling stations. The diaphragm radial stress had been investigated in former researches and two new generatrice of the diaphragm cavity profile had been developed to decrease the diaphragm radial stress. This paper focused on the influence of the generatrice on the cavity clearance volume and compressor flowrate. Experimental and numerical method were applied to compare the diaphragm movements in the cavity defined by different generatrices during the working processing. The flowrates and clearance volume of the diaphragm compressor also were discussed by using experimental method. Furthermore, the effects of the generatrix parameters on the relative clearance volume were analyzed to obtain the optimal parameters value range. The results showed that the diaphragm cavity defined by new generatices had an additional clearance volume between the diaphragm and cavity surface, which was 1.11% and 3.44% of the cavity volume, respectively. And the minimum flowrate decrease rate of the compressor with the cavities defined by new generatrices even reached over 4.11%.