Investigation On Digital Scroll Compressor Air-Conditioning System

The air-conditioning system based on the digital scroll compressor is a new system. Energy-saving and environment protection have become one important topic in refrigeration air-conditioning industry, which has consumed 10 percent of total energy. Especially in the total architecture, air-conditioning systems have taken a large proportion, so thorough research on every part of air-conditioning system is very necessary and important. In order to save energy, we should investigate the efficiency optimization of every link and try to decrease the loss of every link to make the operation of the air-conditioning system match with the whole architecture environment and respond quickly to the architecture heat-load. The air-conditioning system researched in this thesis is totally different from the traditional secondary fluid air-conditioning system. It is a high efficiency and new type air-conditioning system, whose refrigerant is driven by compressor and sent to every room that needs to cool. It needn't water as secondary fluid. This thesis is focused on the air-conditioner driven by digital scroll compressor and its associated system. In order to seek the optimal air-conditioning capacity-adjusting system and the best methods to improve the air-conditioning system efficiency, every link of the digital scroll air-conditioning system is investigated thoroughly.The energy transmission of the air-conditioning system and its associated system combined with environment is firstly analyzed in this thesis, and the working principle of the digital scroll compressor and its application in air-conditioning system are briefly explained. Through the thermodynamics analysis on working conditions of every part and every link in air-conditioning associated system, from the cooling aspect and heating aspect respectively, this thesis points out that the traditional air-conditioning system can't meet the lack-adjustment and over-adjustment problem due to the ambient temperature change. Based on the above, one conception is brought forward, that is, the air-conditioning capacity must change with the change of the ambient temperature and a numerical air-conditioning system must have a compressor with numerical output, which points out a new method for air-conditioning system to become high capacity-adjustment system. According to thermodynamics analysis on digital scroll compressor and air-conditioning capacity-adjustment mathematics model, mathematics models about the relation between air-conditioning associated system capacity and duty-ratio are built in this thesis, the numerical adjustment problem about room heat-load and air-conditioning system capacity is discussed and new method of numerical design combined these two is attempted, and thus thermodynamics models of digital scroll compressor air-conditioning system are put forward. What's more, comprehensive experimental analysis on digital scroll air-conditioning system is done in the ambient labs, thus experimental data are educed, which reflects the air-conditioning system operation conditions.Numerical simulation and calculation are processed on the internal flow field of axial flow fan in digital scroll compressor centralized air-conditioning ventilation system in this thesis by using CFD (Computational Fluid Dynamics) for the first time. The internal flow numerical simulation mainly investigated the formation, development and change processes of the tip vortex and tip vortex core on the blade suction surface, and the complex flow-field structure of the secondary-flow and outlet wake. The comparison between the computational and experimental results verifies the validity and reliability of numerical simulation. It can be used to provide fundamental theory for understanding and mastering the internal flow mechanism and provide helpful reference for improving the internal flow structure and decreasing the fan noise.Experimental measurement is made on the internal flow field of axial flow fan in centralized air-conditioning system in this thesis by using PIV (Particl...