Zhyvytsya V. The scientific and technological fundamentals for design of contact dispersed high speed coolers for ammonia refrigeration plants

The dissertation is devoted to the development of scientific and technological fundamentals aimed for design of the contact dispersed high velocity coolers for ammonia refrigeration plants. The analysis of traditional bubbling intercoolers has shown the dead end in the way to improve their exploitation properties because of unavoidable pressure losses within apparatus through ammonia vapor superheat removing. The gas-dynamic device performing the function of a compressor, called the thermopressor, exploits the possibility of raising the total pressure (phenomenon of heat compression) of a high-speed vapor stream through cooling of the vapor. Nothing stands in the way of installing the thermopressor in refrigeration plant for desuperheating purposes in multi-stage compression. The dissertation illustrates the value of the criterion as a function of operational conditions for two-stage ammonia refrigeration plant. There is a range of Mach number where vapor pressure after cooling is higher than vapor pressure before the cooler. It has been shown the curves of relative pressure change as a function of Mach numbers for vapor cooling between compression stages for different operational conditions in two-stage ammonia refrigeration plant. The velocity of flow in the duck of intermediate cooler in this case should be within the region of 0.3 - 0.6 of Mach numbers. The necessary and sufficient conditions to apply discrete pulse input and power transformation have been analyzed. The same approach has been applied to oil cooling in oil flooded screw low stage compressors. It was shown that because mass flow rate of oil is considerably higher, the properties of the flow are completely determined by oil flow. In this case paying by refrigeration capacity decrease (6...8%) the water cooling system could be avoid completely. The experience of exploitation more than 60 of the above intercoolers has shown that they are quite effective and reliable devices. The main advantage of their use is the higher safety of refrigeration plant exploitation.