ANALYSIS OF INITIALLY SUBCOOLED LEAKAGE FLOWS IN A NARROW THROUGH-WALL CRACK AT LOW REYNOLDS-NUMBERS

摘要

For the investigations of leakage flow rates with reduced stagnation pressure (maximum 1.0 MPa) and stagnation temperature (maximum 170 °C) compared to real plant conditions, the Leakage Flow (LF) test rig is used. The design of the test rig enables experimental measurements of leakage flow rates through cracks with different shapes, sizes and wall thicknesses. In the paper, experimental results of leakage flow measurements for one artificial through-wall crack-geometry with a rectangular shape are presented. The fluid conditions of the investigations vary in the pressure range from 0.2 MPa to 1.0 MPa with a maximum temperature of 170 °C. The experimental values in the single-phase regime up to 90 °C are used to calculate the overall loss coefficient respectively the friction factor and are compared to theoretical models. The results at elevated temperature from 100 °C to 170 °C are discussed considering the subcooling of the fluid and compared to theoretical values calculated by the modified Bernoulli equation.