Research of the thermogravitational convection influence on heat exchange via the example of liquid metal flow through the active zone of a fast nuclear reactor

Аuthors

Novikov A. О.^1*, Razuvanov N. G.^2**, Sviridov V. G.^1***

1. Moscow Power Engineering Institute (National Research University), 14, Krasnokazarmennaja St., Moscow, 111250, Russia
2. Joint Institute for High Temperatures of the Russian Academy of Sciences, 13, Izhorskaya str., Moscow, 125412, Russia

*e-mail: andnov92@mail.ru
**e-mail: nikita.razuvanov@mail.ru
***e-mail: sviridovvg@gmail.com

Abstract

The purpose of this experimental study is to obtain information on the distribution of wall temperature along the channel perimeter and heat transfer coefficients during the liquid metal coolant flow in models simulating of the fast reactor core elementary cell. The test area is a com- plex geometry formed by three sections of a round tube simulating the fuel elements which separate from each other by partitions. The experiments were carried out using RK-1 mercury loop located at the Department of Engineering Thermophysics, NRU «MPEI». The research was done with a probe technique: a swivel-type probe was used, which allows us measuring the required characteristic at any point of the studied channel cross-section, including on the wall. To determine the heat transfer coefficients, the values of the wall temperatures obtained at the moment of touching the thermocouple of the channel wall by the probe tip were used. In the experiments we used an automated scientific research system (ASRS), which provides a large amount of infomation in a short time. The article shows the results of experiments performed in a wide range of regime parameters (Gr, Re numbers). The generalization of the experimental data is presented as an empirical formula for the dependence of the Nusselt number on the Peclet number. The thermogravitational convection influence at low flow rates of liquid metal is reflected in the character of the Nusselt number dependence on the Richardson number and Peclet number. The obtained experimental data significantly extend the existing database for codes verification used to calculate the velocity and temperature fields in channels with a complex shape cross-section, simulating real cross-sections in which liquid metal coolant circulates, cooling the nuclear reactors core.

Keywords:

nuclear reactor, experiment, probe method, thermogravitational convection, heat transfer, liquid metal.

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