Investigation on the influence of water injection on twin screw water vapor compressors' working process

Due to the reason of water injection, twin screw water vapor compressor can realize high pressure ratio and saturated temperature lift of compressed vapor. In order to investigate the influence of injected water on the water vapor compressor's performance, a thermodynamic model of the working process of water injected twin screw water vapor compressor is established and validated experimentally. And the influence of a number of operating parameters is discussed and analyzed. According to the results, it is found that water injection can make the compressing process closer to isothermal compressing. The evaporation of injected water mainly happens at the end of compressing and discharging process in real operation. The high pressure vapor in the discharge chamber has little influence to the compressing process when the compressor operates at under-compressing. According to the simulation results, the temperature of injected water affects the working process and efficiency of the compressor little. For different operating conditions, the mass flow rate of injected water should be increased with the rotor speed to guarantee a saturate discharge temperature.