Performance analysis of double-stage perforated plate flowmeter for cryogenic fluids

Abstract

In this paper, a novel flowmeter with a double-stage perforated plate structure is proposed, and its pressure drop and flow coefficient are numerically compared with the commonly used single-stage perforated plate structure for the cryogenic fluid measurement. The numerical calculations are based on the Realizable k-ε turbulence model and consider the influence of cavitation with thermal effects, which is validated by modeling the cavitating flow of liquid nitrogen over the hydrofoil in the publications. The influence characteristics of the thickness of the single-stage perforated plate on the performance are firstly clarified. Then the emphases are focused on the analysis of the effects of the gap of the double-stage perforated plates on the discharge coefficient, the pressure loss coefficient and the deviation coefficient. The results reveal that compared with the single-stage perforated plate, the double-stage one with the optimized gap has a smaller pressure drop and more horizontal flow coefficient profile with the Re number. The reason for the performance improvement is primarily ascribed to the “thickness effect”, which is explained in detail. While, the increase in the number of stages makes the cavitation more likely to occur, which leads to a smaller Re range of the horizontal flow coefficient profile. The results can be used as a useful reference for the design of the cryogenic differential pressure flowmeter.