Optical visualization as an effective tool for studying the flow structure in a small-sized centrifugal electric pump

Abstract

The article is devoted to the substantiation of the need for optical visualization of the structure of a 2-dimensional flow in small-sized centrifugal electric pumps of the spacecraft thermal control system. Reducing the size of the interblade channels of the pump impeller makes it impossible to use traditional methods of flow sensing due to disturbances introduced by the probes. Due to the lack of experimental data, in the study of flows in small pumps, a flow model developed for full-size centrifugal pumps is used. The most common of these are the Euler jet model or the two-zone jet-trail model. Studies by numerical methods based on these models cannot be verified for adequacy to real flows due to the lack of experimental data necessary to validate the results obtained. Under such conditions, the study of the flow structure by experimental methods, in particular, using optical visualization by the method of indicator washable coatings in the near-wall layer of the interblade channels of the impeller of pumps, becomes important. This article describes: 1) the technology of imaging; 2) structural elements of the flow, which are identified in the flow patterns in the near-wall layer; 3) results of visualization of the flow in the impellers of centrifugal pumps with a diameter of 41·10-3 m. New data are obtained on the structure of the flow under flow regimes in the non-self-similar zone of the Reynolds number in relative motion.