Measurement of the Thermal and Velocity Fields in the Liquid Phase of Turbulent Subcooled Bubbly Boiling Flow

To investigate the thermal and velocity fields in the liquid phase of turbulent subcooled boiling flow, local measurements were made in the bubbly regime. The boiling flow, of Refrigerant-113, was created in a vertical annular channel whose inner wall was heated. The technique involves the simultaneous use of a two-component laser Doppler Velocimeter (LDV) for measuring the velocity field, and a fast-response cold-wire for measuring the temperature field. The LDV measuring volume (m.v.) dimensions in the liquid were: 290 microns spanwise length × 55 microns diameter. The 3.8 micron diameter tungsten cold-wire had an active length of 300 microns and was placed 250 microns downstream of the center of the LDV m.v. The cold-wire in conjunction with an active phase-lead compensation circuit had a temperature response time constant of 0.3±0.02 ms in the liquid flow. To validate the measurement technique, the velocity and thermal fields were first measured in heated single-phase liquid flow in the same channel and compared with the corresponding computed fields. Selected results are presented. Next, measurements in boiling flow at one experimental condition are presented and their intended use in multidimensional two-fluid modeling of the flow is briefly discussed.