An optimization study on the seal structure of fully-rotary valve energy recovery device by CFD

Abstract

Leakage in isobaric energy recovery devices (ERDs) is inevitable. Three seal structures are introduced and studied for a fully-rotary valve energy recovery device (FRV-ERD) to reduce leakage. Effects of pressure difference and geometrical parameters of seal structure on leakage are investigated and compared for different seal structures. Results show that, as the key component of this ERD, the fully-rotary valve (FRV) achieves its best seal performance with the bilateral seal. For the FRV-ERD of design parameters, both the efficiency and required clearance are improved by using the bilateral seal to replace the original seal. The calculated efficiency is improved from 89.48% to 92.05% at the clearance of 30 μm under operating pressure and the required clearance increases from 18.1 μm to 20.4 μm. Based on the results of the optimized bilateral seal, an approximate leakage rate equation is proposed and can be used for design calculation. The performance of FRV-ERD with the optimized bilateral seal is improved greatly. Compared with FRV-ERD with the original seal, the efficiency of FRV-ERD with the optimized bilateral seal is improved from 89.48% to 96.33% at the clearance of 30 μm under operating pressure, and the required clearance increases from 18.1 μm to 29.5 μm, easing machining difficulty greatly.