Study on Thermal Characteristics of the Regenerative Heat Exchanger Available to Purchase

The regenerative heat exchanger is widely used in nuclear power plants and research reactors. It is composed of the regeneration section and the cooling section. The heat transfer mainly occurs at the cooling section, while the regeneration section is designed to reduce the temperature difference between the hot and cold fluids and weaken the damage to the heat exchanger due to the existence of thermal stress. Meanwhile, some heat is also can be recovered through the regeneration section. This paper mainly aims to analyze the thermal characteristics of the regenerative heat exchanger according to its structure properties, and provides some suggestions for regenerative heat exchanger design based on the influence of some key factors on thermal characteristics. The results show that improving the outlet temperature in the regeneration section primary side can both reduce the heat exchange areas of the regeneration section and the cooling section, but this will rise thermal shock and increase the operation safety risk. The baffles arrangement will enhance heat exchange capacity, and the heat exchange area decreases with the baffle gap height increasing. With the heat exchange area margin of the regeneration section improvement, the actual power will gradually reduce. The measures, including increasing secondary water flow or taking a corresponding margin about 52.8%∼59.2% that of the regeneration section for the cooling section heat exchange area, can be taken to overcome the adverse effects of the margin on the regenerative heat exchanger. More heat exchange areas of the regeneration section and the cooling section are required to satisfy the rated power with the fouling thermal resistance of the primary water increasing. Moreover, adopting a lower fouling coefficient favors the generative heat exchanger running under the design power.