Temperature measuring device for wall temperature of fine rod narrow gap under motion condition

Abstract

The invention discloses a temperature measuring device for the wall temperature of a fine rod narrow gap under a motion condition. The temperature measuring device comprises heating element pipes andone or more sheathed thermocouples. One or more temperature measuring holes are formed in the outer circumferential walls of the heating element pipes in the circumferential direction of the heating element pipes. Compensating conductors of the sheathed thermocouples penetrate through the heating element pipes and then extend outwards. The outer walls of the compensating conductors of all the sheathed thermocouples are sequentially wrapped with high-temperature isolating coatings and high-temperature isolating adhesive tapes. The heating element pipes are filled with high-temperature isolatingsilicone. Through the technical scheme, wall surface temperatures of different positions of all the heating element pipes of a high-temperature fine rod bundle narrow gap fuel assembly can be accurately measured under the motion condition, the sheathed thermocouples do not shed or are not subjected to an insulation failure, temperature measuring parts conduct temperature measuring in the rod bundle heating element pipes, thus flow fields and temperature fields beside the heating element pipes cannot be interfered, and thermo-technical performance parameters such as the heat transfer coefficient and the critical heat flux density of the fuel assembly can be accurately obtained by carrying out heat transfer experiments of the fuel assembly under the motion condition.

Description

technical field [0001] The invention relates to the technical field of thermal-hydraulic research of reactors, in particular to a thin-rod narrow-gap wall temperature measuring device under motion conditions. Background technique [0002] The thin rod bundle fuel assembly is a new type of advanced core assembly. The design of the fuel assembly reduces the volume of the reactor core by using thin fuel element rods and reducing the distance between the fuel element rods, which greatly improves the power density and fuel consumption of the core. consumption depth. Floating nuclear power plants, marine nuclear power and other reactor core structures can use thin rod bundle structure fuel assemblies, but these nuclear power plants will be affected by ocean motion conditions during operation, and the external force field generated by motion conditions will change the inlet and outlet of coolant channels The effective height difference and acceleration field can change the charact...

AI Technical Summary

Problems solved by technology

In view of the particularity of the structure of the existing rod bundle fuel assemblies and the complexity of the component flow field and temperature field under motion conditions, which leads to the difficulty in obtaining thermal parameters such as the wall temperature of the fuel assembly, the applicant simulated the rod bundle fuel assembly When carrying out the experimental research on heat transfer characteristics, the metal round tube is used as the heating element tube, and at least one temperature measuring hole is set in the heating element tube, and the armored thermocouple is placed in the temperature measuring hole after passing through the heating element tube. Inside, the outer wall of the compensation wire of the armored thermocouple is wrapped with a high-temperature insulating layer and a high-temperature insulating tape in sequence. By filling the heating element tube with high-temperature insulating silica gel, the armored thermocouple and the heating element tube are combined into a whole. After the armored thermocouple is installed, a plurality of heating element tubes are welded into a thin rod bundle fuel assembly to determine the temperature measurement point, and then the temperature measurement hole is opened at the temperature measurement point, and then the temperature starts from the inside of the heating element tube. Detection, to achieve accurate measurement of the temperature of the local wall surface of the heating element tube by the armored thermocouple in the moving state; among them, the heating element tube needs to be energized to generate heat in the heat transfer experiment of the fuel assembly, and the shell of the armored thermocouple is usually made of stainless steel Material, thin rod bundle simulates the internal and external gaps of the element rods of the fuel assembly are very small. When the heating element tube is in motion, the armored thermocouple shell is easy to contact with the inner wall of the heating element tube and become charged. Once the armored thermocouple shell Conducting electricity cannot guarantee the accuracy of thermocouple measurement. For this, the applicant opened a temperature measurement hole on the outer wall of the heating element tube, and the end part of the armored thermocouple is placed in the temperature measurement hole and protrudes from the temperature measurement hole. The outermost side can not only fix the armored thermocouple on the inner wall of the heating element tube to realize the positioning of the armored thermocouple, but also prevent the temperature measurement component from interfering with the flow field and temperature field of the external flowing medium of the heating element tube , and finally realize the accurate measurement of the wall temperature at different positions of the heating element tube in the heat transfer experiment of the fuel assembly

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