Rotor Structure Optimization of a Twin-Screw Expander for Natural Gas Pressure Energy Recovery Based on an NGO-SDERIME Hybrid Algorithm

To improve the efficiency and output power of the twin-screw expander used in natural gas pressure energy recovery, a hybrid NGO-SDERIME algorithm is proposed for structural optimization, with the structural parameters of the male and female rotors selected as the optimization design variables. First, the enhanced Rime Ice Optimization (RIME) algorithm is adopted to perform hybrid improvement on the Northern Goshawk Optimization (NGO) algorithm; then, the stability and superiority of the proposed hybrid algorithm are verified by using a suite of benchmark test functions; finally, the algorithm is applied to the structural optimization of the twin-screw expander, followed by numerical simulation and experimental verification. The results indicate that, compared with other existing algorithms, the proposed NGO-SDERIME hybrid algorithm shows excellent convergence and strong optimization performance. After optimization using this algorithm, the output power of the screw expander increases by 5.5%, the high-speed leakage area is significantly reduced, the isentropic efficiency improves from 75.1% to 78.1%, and the average mass flow rate increases from 18.42 t/h to 18.72 t/h.