Recently, China`s first liquid metal sodium-supercritical carbon dioxide printed circuit heat exchangers (PCHEs) developed by China Shipbuilding Institute 725 in conjunction with China National Nuclear Corporation Atomic Energy Institute and Hefei General Machinery Research Institute Co., Ltd. completed the test bench assessment and passed the expert successfully Group acceptance, product technology reached the international advanced level. This is another breakthrough achieved by the PCHE product of the 725 Institute in the field of nuclear energy after the field of high-efficiency thermal power generation, ocean engineering, and hydrogen energy.
The sodium-supercritical carbon dioxide heat exchanger is one of the key equipment of the fourth-generation nuclear energy-liquid metal-cooled fast reactor innovative power conversion system. It needs to achieve high-efficiency heat exchange under harsh conditions such as high temperature, high pressure, and strong corrosion. The products that passed the inspection this time are a new generation of PCHE products developed by the 725 Institute in view of the large difference in the flow and heat transfer characteristics of the cold and hot sides. It can be used in sodium-cooled fast reactors, lead-bismuth fast reactors and other liquid metal cooling The power conversion system of the reactor.
In the process of new product development, the project team innovatively proposed a heat exchanger core type with asymmetrical structure of the mixed channel in order to solve the problems of liquid metal sodium with good heat transfer characteristics, poor fluidity, and conventional PCHE easily causing liquid metal sodium to block. Breakthrough key technologies such as structural design of dissimilar channels on the cold and hot sides, large channel heat exchange plate etching, core diffusion welding, and PCHE inspection and evaluation. In December 2019, with the joint efforts of the three units, the prototype sodium-supercritical carbon dioxide heat exchanger was developed and delivered on schedule. In May 2020, the heat exchanger prototype passed the heat transfer performance experiments under various working conditions, which verified the rationality of the design and structural reliability.
As a subversive, compact and efficient microchannel heat exchanger, PCHE has the advantages of high heat exchange efficiency, low temperature and high temperature resistance, high pressure resistance, and high reliability. The new generation of PCHE products delivered this time has further expanded the application fields of PCHE. It is not only the first choice for high-efficiency and compact sodium-supercritical carbon dioxide heat exchangers, but also can be used for heat exchange in sea water, flue gas and other media. Application prospects.
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