twin screw expanders profile optimization using surrogate-‎based modelling

Twin screw machines can be used as an expander to recover the lost power in various processes causing pressure energy loss. twin screw expanders (tses) have caught the attention of many researchers due to low capital, maintenance and operation costs, long lifespan and their application in two-phase fluids. however, substantial efforts required to enhance their performance. this research describes the optimization of the profile of a tse with 4-6 lobe configuration - using surrogate-based modeling (sbm). to do so, based on the in-house code developed within fortran, a tse profile is designed and validated against available data. then, a mathematical model is developed via of experiments (doe). next, the effects of four main profile parameters are investigated on the expander performance in the entire design space. finally, an optimized combination of parameters is offered using a multi-objective genetic algorithm. 3d computational fluid dynamics (cfd) results show that the optimized profile had more than 7% exergy efficiency compared to the base profile.