Internal flow field and heat transfer investigation inside the working chamber of a scroll compressor

摘要

The paper analyzes the influence of specific parameters such as scroll vane shape, discharge pressure and the rotational speed of a scroll compressor, on the thermal balance inside of a working chamber with tangential leakages. A two-dimensional numerical model of unsteady flow including leakages between working chambers and a special numerical grid deformation procedure is proposed. The developed set of governing equations of mass conservation, momentum, and energy is solved using the Finite Volume Method. In order to determine the upper limit of the heat transfer between vanes and the working medium - air and carbon dioxide, three cases such as: both vanes are assumed to be adiabatic, on one vane a constant temperature is applied and both vanes held at a constant temperature, are investigated. The average values of the Nusselt number inside a working chamber were elaborated and compared with other relations available in the literature, called the lumped model. It was found that tangential leakages have a high effect on thermal processes. A new relation to the Nusselt number including leakages is proposed. After the introduction of the correction factor, the deviation from the lumped model is reduced to less than 15% compared to the numerical model.