The role of flow characteristics in corrosion-erosion of tube inlets in the inlet channel of shell and tube heat exchangers

As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant.

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Investigating the hydraulic resistance in the flow part elements of pneumatic systems and heat exchangers

Journal of Physics Conference Series ◽

10.1088/1742-6596/2057/1/012015 ◽

2021 ◽

Vol 2057 (1) ◽

pp. 012015

Author(s):

A S Pugachuk ◽

N F Fominykh ◽

E O Kalashnikova ◽

Yu A Gavrilova

Keyword(s):

Hydraulic Resistance ◽

Heat Exchangers ◽

Power Plants ◽

Selective Laser Sintering ◽

Additive Technologies ◽

Distributed Power Generation ◽

Coefficient Of Hydraulic Resistance ◽

Flow Part ◽

Shell And Tube

Abstract The article deals with the development of shell-and-tube heat exchangers for the needs of power engineering, based on additive technologies, in particular, selective laser sintering technology with new configurations of heat exchange surfaces. The role of heat exchangers in microturbines, the most common units of power plants of small distributed power generation, is considered. To intensify heat transfer and increase the efficiency of microturbines, it is proposed to use various configurations of flow channels of shell-and-tube heat exchangers made on the basis of additive technologies. Mathematical modeling and experimental study of a gas medium flow in the tubes of a heat exchanger are carried out. The dependences of the coefficient of hydraulic resistance between the surface of inlet and outlet of gas from tubes of various configurations on the Reynolds number are obtained. The results of the experiment allow us to conclude that the resistance of spiral-shaped tubes is slightly higher than the resistance of tubes with three ribs.

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