Experimental And Theoretical Studies On A Bubble Pump Used For The Auto-Cascade Diffusion-Absorption Refrigeration System

With the development of the society and economy, the problem of energy use and saving is becoming extremely significant. In the refrigeration technology, the diffusion absorption refrigeration system which can make use of low-grade waste heat to produce cooling capacity with the advantages of no moving parts, no noise, no vibration and high reliability, has attracted more and more attention in recent years. The auto-cascade diffusion absorption refrigeration cycle which employed DMF as the absorbent, and R134a&R23 as the refrigerant owns the advantages of the traditional one, but also the ability to produce cooling capacity at even lower temperature. The generator named bubble pump, is the key component of the auto-cascade diffusion absorption refrigeration system. The characteristics and performance of the generator have great effect on the continuous and stable operation of the cycle, as well as the efficiency of the system. Therefore, it play an important role in the design and optimization of the system. Both theoretical and experimental studies were carried out in this thesis and the main research contents are as below:1 The summary of the present research status of bubble pump in diffusion absorption refrigeration at home and abroad, based on which the significance and future research direction of the thesis are pointed out.2 The theoretically analysis and design of the bubble pump model was set up according to the Mass Conservation equation, Energy Conservation equation, Momentum Conservation equation, the Boiling heat transfer theory and Two-phase flow theory,, based on which we make clear of the effect of the parameters on the operation conditions and principles of the bubble pump.3. Thermodynamic calculation of the bubble pump performance experimental device and the selection calculation of the key components. The built up of the experimental device, and the improvement of the generator form. 4. The experimental research on the effect of the parameters such as the pipe diameter, flow pattern, heat flux, concentration and system pressure on the performance and efficiency of the bubble pump, and the comparison with results of the bubble pump model calculation, based on which the general law of the design of the bubble pump of the auto-cascade diffusion absorption refrigeration system was summed up.