RESEARCH ON DISCHARGE COEFFICIENT OF COOLING HOLES ON FEEDER TUBE

The main air flow supplied in the feeder tube is delivered to cooling holes with axis perpendicular to the main flow.This crossflow pattern exerts a significant influence on the hole discharge coefficient.The experimental investigation of the hole discharge coefficients and the measurement of static pressure distribution along the tube axis have been completed.It is shown that the discharge coefficient increases as the ratio of the orifice thickness to diameter and the velocity head ratio between orifice flow and tube flow increase.But the discharge coefficient approaches to a constant when the velocity head ratio is greater than 100.Empirical formulas have been dedueed from the experimental data.The static pressure distribution along the tube and the air flow rate allocation for the holes have been calculated by using the general air system computer program developed by author.The results ageree with the experimental data well.