Model for Carried Out Liquid Fraction from Accumulator of Compressor Used in Room Air-Conditioners

To prevent issues such as liquid hammer or oil starvation resulting from excessive or insufficient liquid carried from the accumulator in air conditioner compressors, controlling the liquid mass within reasonable limits is essential. This requires an accurate prediction method for evaluating the liquid carryover. The purpose of this study is to develop a model to predict the mass of liquid carried from an accumulator and to validate this model experimentally. The flow process of the refrigerant-oil mixture is divided into four subprocesses: vapor-liquid phase change, vapor-liquid interphase mass transfer, inlet tube injection flow, and outlet tube convergence flow. Four submodels are established to describe these subprocesses, and an algorithm based on the backward difference method is developed to solve them. An experimental apparatus is set up to measure the liquid carryover from the accumulator. The experimental results show that the deviation between the model predictions and experimental values is within ±3%, with an average deviation of 0.7%. The proposed accumulator model can be used to design the structural parameters of the oil return hole, avoiding liquid hammer and oil starvation in compressors.