A Technique for Scanning Probe Measurement of Temperature Fields in a Liquid Flow

For designing different heat and power equipment with a wide range of applications, it is necessary to measure the fields of thermophysical characteristics (temperature, pressure, velocities, etc.) in as much detail as possible. At the same time, the deployment of complex diagnostic methods is often impossible. Therefore, it is most practical to use movable probes that move in the flow and make measurements at separate points. The use of such scanning measurement methods is a complex task that requires the solution of many mechanical and thermophysical problems. The techniques of scanning probe measurements for determining thermal characteristics in the flows of various media are described. A review is given concerning the development of probe-based investigation methods since the 1960s. Joint probe developments concerning the probes made by the scientific group of the Engineering Thermophysics Department of the National Research University Moscow Power Engineering Institute and the Joint Institute for High Temperatures, Russian Academy of Sciences, for two-dimensional and three-dimensional temperature and velocity measurements in water and mercury flows are presented in detail. The experience in the development and use of scanning probes is summarized in three main designs, such as a hinged probe, a probe with eccentricity, and a longitudinal probe. Descriptions, methods of application, and the features of their operation are considered for these designs. The results obtained by using the probes of various designs in the course of experiments with water and mercury are considered. The choice of a required technique is substantiated depending on the preset conditions of the problem, such as the geometric characteristics of the investigated area, the presence of a magnetic field, the influence of thermal and gravity factors.