Dạng xoắn bằng phương pháp mô phỏng cfd a study to evaluate the effects of geometrical parameters and flow parameters on the exergy efficiency of tube-in-tube helical heat exchanger by cfd simulation

The paper presents research on the influence of geometrical and operating parameters on the exergy efficiency of tube-in-tube helical heat exchanger by using numerical simulation (CFD). The analytical solution for the mathematical model involving energy, the effectiveness and the exergy efficiency of a tube-in-tube helical heat exchanger is obtained using an EES (Engineering Equation Solver) program. The results of the study show that, the exergy efficiency increase with increasing the Reynolds number of hot water (Reh), decreasing the Reynolds number of cold water (Rec), increasing coil diameter (Dc), decreasing the coil pitch. In the scope of the survey with Reynolds numbers of hot and cold water (Reh and Rec) from 9000 to 27000 and 10000 to 30000, respectively; coil diameter (Dc) from 60 mm to 120 mm the coil pitch (hc) from 20 mm to 30 mm, then the exergy efficiency of tube-in-tube helical heat exchanger obtained maximum of e = 6,607% corresponding to Reh = 27000, Rec = 10000, Dc =90 mm (Dc/d = 6), hc=25 mm (hc-d = 10 mm).