螺杆蒸汽压缩机工作过程喷水冷却特性研究

Investigation on the Influence of Water Injection on Twin Screw Water Vapor Compressors' Working Process

喷水能够提高螺杆蒸汽压缩机的压比和饱和温升,扩展蒸汽压缩机的应用范围。为研究螺杆蒸汽压缩机的喷水冷却特性,建立喷水螺杆蒸汽压缩机的数学模型,考虑喷入水与压缩蒸汽的换热蒸发及其泄漏闪蒸,并试验验证了模型的准确性。利用所建数学模型,分析与讨论压缩机压比、喷水量、喷水温度及转速对压缩机工作过程的影响。研究结果表明,喷水不仅可以降低排汽温度、使蒸汽压缩机稳定运行,还可以使压缩过程更接近等温过程;压缩机实际运行时喷入水主要集中在压缩过程后期及排汽过程蒸发;压缩机欠压缩运行时,排汽腔内蒸汽对压缩过程影响不大;若压缩蒸汽任一转角都能被冷却至饱和,则喷水温度对压缩过程及运行效率基本没有影响;为了有效控制排汽温度,喷水孔口水流量需要随压缩机转速做相应的调节。

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.