Experimental study on flow uniformity of cold He riser in a modular high temperature gas cooled reactor

Abstract

The primary system of a modular high temperature gas cooled reactor (HTR-PM) uses He as a coolant. The mass flow of He in the loop is an important thermal parameter for performing the reactor protection function and calculating the reactor thermal power. Therefore, a complete understanding of the flow distribution law governing each pipeline is necessary for determining the position suitable for installing an elbow flowmeter. From the perspective of computational fluid dynamics (CFD), a mathematical model suitable for the experimental system was derived. The similarity criterion of the experimental system was then obtained using the similarity theoretical analysis. That is, to ensure the geometric similarity and Reynolds similarity between the water experimental system and actual system, the flow distribution obtained from the differential pressure experiment must be consistent. Furthermore, the system was tested under different flow on the high-precision experimental platform. A numerical model of HTR-PM was established. The results from experiments and numerical simulations revealed that, under different flow rates, the pressure levels inside and outside the sensor are governed by the same law. Moreover, the pipe position closest to the average flow was selected as the installation position of the elbow flowmeter.