Research On The Characteristics Of Wet Steam Compression Process

In the field of storage air-condition and dehumidification, it uses aqueous lithium bromide (H₂O-LiBr) as working fluid and the refrigerant is water. The system needs water vapor compressor. Thought water is a good refrigerant, it is difficult to be used directly in a common compression refrigeration system due to its very low pressure and vapor density at the evaporation temperature. However, the compressor charge pressure is only dependent on the generation pressure in the system. The generation pressure can be raised before the vapor sucked into compressor. But the charge temperature of compressor also increases with the generation pressure rising. If the vapor is sucked and compressed directly in dry compression mode, the discharge temperature will exceed 200℃. In order to restrain the discharge temperature of water vapor compressor and utilize the energy of compressed water vapor, the wet compression mode must be taken into consideration in the system. The temperature reduces with the vapor vaporizing and the discharge vapor saturated.Water is refrigerant and cooling liquid in the special wet compression. On the basis of thermodynamics, the paper analyzes heat transfer between water and water vapor in the wet compression process and presents the mathematic model of the working process of twin-screw compressor considering the leakage of water and water vapor during the compression. Basing the established model and the character dates of water and water vapor, wet compression process of the screw compressor is simulated and calculated by the numerical method. The changing of pressure with the angle is described;the results indicates that wet compression not only decrease the discharged temperature, but also saves the power work;the dates of water droplet diameter versus the dry degree of wet steam is given in the paper;The influence of the dry degree of wet steam and water droplet diameter on the discharge temperature and compression power is discussed. This paper's result can provide a reference to design new type of water vapor compressor and help extend the area of using water vapor compressor.