跨临界CO_2节流短管内相变机理研究

RESEARCHES ON THE FLASHING MECHANICS OF TRANS-CRITICAL CO2 FLOWING THROUGH SHORT TUBE ORIFICES

跨临界CO2节流前为超临界流体,节流前后的压差达7.0 MPa,加之其热物性与常规制冷剂明显不同,使得跨临界CO2节流相变过程比常规制冷系统复杂的多。本文以节流短管为研究对象,通过测量节流短管沿程压力、温度分布的方法,分析CO2节流相变过程特点,掌握其相变规律,为进一步理论模型的建立及系统设计提供指导方向。

Refrigerant CO2 remains trans-critical gas fluid before entering the short tube orifice. The pressure differential between the upstream and downstream of the short tube is high to 7.0 MPa. In addition, some of the thermal and physical properties greatly differ from the general refrigerants. All these factors indicate that the flashing process of trans-critical CO2 flowing through the short tube orifice is more complicate than the general refrigeration cycle. The short tube orifice was selected as the object to study. The flashing characteristics and general laws about the trans-critical CO2 flowing through the short tube orifice were investigated through measuring the pressure and temperature distribution along the tube. This will provide instructions for the trans-critical CO2 system design and the further theoretical research.