Experimental investigation on pressure drop characteristic of R410A through short tube orifices

- The short tube orifice throttling semi-empirical model with refrigerant R410A was set up for the first time.
- The semi-empirical impedance model ΔP=s1+s2LD5G2 was established.
- The short tube orifice throttling model has a high precision and a large scope working condition.

The pressure drop characteristic experiments of R410A through short tube orifices (diameter ranged from 0.7 to 1 mm, and length ranged from 5 to 15 mm) were performed under specific condensing pressure, evaporating pressure and sub-cooling degree conditions. A quadratic regression semi-empirical benchmark model was established based on the impedance calculation method. According to the benchmark model, the pressure drop characteristic experiments were performed under condensing pressures ranged from 2500 to 3100 kPa, evaporating pressures ranged from 900 to 1200 kPa and sub-cooling degrees ranged from 3 to 9 °C. A semi-empirical universal model of pressure drop characteristic of R410A through short tube orifices is developed. The model can cover the test range of working conditions and refrigerant mass flow rate. The model is used to predict the pressure drop of R410A through two kinds of the short tube orifices under a variety of working conditions, and the deviation between the predicted value and the measured value is within ±10%. The experimental results of air conditioner matching validation experiments show that the air conditioning system don't need to adjust with the short tube orifices replace the capillary tubes.