Study on the wall-approaching film formation characteristics of water injected in a single screw steam compressor

Abstract

To investigate the wall-approaching film formation (WAFF) mechanism of water injected during the compression process of single screw compressor, then to realize reasonable control of water injection parameters, a numerical simulation of water and steam two-phase flow inside the compression chamber during the compression process was carried out. The WAFF characteristics of water injected inside the compression chamber and the influence laws of the key parameters such as water injection angle (IA), injection velocity (IV), injection mass flow rate (IMFR), screw rotor rotational speed (SRRS) and injection hole spatial position (IHSP) on the WAFF characteristics were analyzed. The results show that the water injected into the chamber forms a water film by approaching the wall. With the increase of IA and IV, the effective water film average thickness (EWF-AT) and surface area (EWF-SA) show an increasing trend. In the process of IMFR growth, EWF-AT and EWF-SA exhibit maximum values. Considering the goal of minimizing the injection power consumption, the IA of 70°, IV of 30 m·s−1 and IMFR of 0.3 kg·s−1 were determined as the optimal water injection parameters. Selecting the appropriate IMFR, SRRS and IHSP will effectively increase EWF-AT and EWF-SA, then to prevent leakage.