Study of vapor ejector performance on ejector throat diameter

The 2D axisymmetric, real gas model was developed to calculate the ejector in the ejector cooling system. The calculation is to obtain the effect of ejector throat diameter on ejector performance. There is an optimum ejector throat diameter De*(17mm) with the giving calculation operating condition and the other geometry parameters. When De=De*, the entrainment ratio reached the maximum value; when De>;De*, the refrigerant flow backward the entrainment inlet; when De<;De*, the entrainment ratio increased with the increase of AR. The critical back pressures (Pc*) on the different De have obtained. When De is larger, Pc* is lower; De is smaller, Pc* is higher. When De<;12mm, ejector can´t work even if the back pressure is super low. The change of the ejector performance is caused by the change of shock wave; the change of shock wave is the result of the change of ejector throat diameter.