Authors & Affiliations
Pisarevsky M.I., Mohiuddin S., Golyaev D.I., Fedoseev V.N.
National Research Nuclear University “MEPhI”, Moscow, Russia
Pisarevsky M.I. – Senior Lecturer. Contacts: 31, Kashirskoe shosse, Moscow, 115409. Tel.: +7 (495) 788-56-99; e-mail:
Mohiuddin S. – Master's Degree.
Golyaev D.I. – Graduate Student.
Fedoseev V.N . – Associate Professor, Cand. Sci. (Tech.).
During the operation of the NPP power equipment, a natural roughness is formed on the heat exchange surfaces, which can serve as reasons for reducing the coolant flow rate due to an increase in friction resistance. The article proposes a method for estimating the size of sediments on structural elements in units of equivalent sand roughness. The movement of a coolant in a narrow annular channel with one rough wall is considered, since it is a simulation model of an equivalent cell of a fuel element. The channel is divided into two layers by a line of zero shear stresses. Each layer has its own thickness, the average speed of the coolant, the law of change of the hydraulic resistance coefficient. A formula is obtained for calculating the coefficient of hydraulic resistance of a rough layer, according to the size of sediments is determined. Validation of the methodology was carried out on three artificial roughness and one natural roughness created by a sandblasting machine. Two-dimensional rectangular, trapezoidal and triangular protrusion are considered as artificial roughness. The difference between the calculated values of the equivalent sand roughness from the reference does not exceed 20 %. The dependences of the pressure drop growth along the length of the annular channel on the size of the equivalent sand roughness are drawn in graph for fixed Reynolds numbers. This dependence on the measured pressure drop allows us to determine the size of the protrusions of sediments.
roughness, natural roughness, artificial roughness, equivalent sand roughness, deposits, hydraulic resistance coefficient, annular channel, rectangular channel, rough layer
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