A variable density optimization method for liquid helium storage tank composite variable density multi-layer insulation structure

Abstract

The patent of the present invention discloses a variable density optimization method for a composite variable density multilayer insulation structure of a liquid helium storage tank. With the increase of the spacer, the heat conduction of solid decreases with the increase of the spacer. Therefore, this calculation method integrates the changing laws of these two aspects, and establishes a layer density optimization method for composite variable density multilayer insulation structures. The position of each added spacer in the composite multi-layer insulation layer is optimized layer by layer, and the number of spacers is continuously increased until the total heat flux reaches the minimum value, and the number of spacers corresponding to the minimum value is the optimal spacer for this layer Brush the amount, and use the same method to optimize the rest of the layers. Through optimization, the optimized configuration of the composite variable density multi-layer insulation structure of the liquid helium storage tank is realized, which further improves the cold storage performance of the liquid helium storage tank and reduces the evaporation loss of liquid helium.

Description

technical field [0001] The invention relates to a variable density optimization method for a liquid helium storage tank with a composite variable density multi-layer heat insulation structure, and belongs to the technical field of low temperature liquid passive thermal protection. Background technique [0002] Helium is a monoatomic inert gas, colorless, odorless and non-toxic. It is the substance with the lowest critical temperature found by human beings so far. Liquid helium has extremely low critical temperature, high-efficiency convective heat transfer characteristics and high quantum mechanical zero-point energy. Therefore, it has played an important role in the fields of space exploration, military industry, refrigeration, medical treatment, semiconductor and magnet production, superconducting experiments, and optoelectronic product production. irreplaceable role. At present, helium is mainly transported in liquid phase, but the extremely low temperature of liquid hel...

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Problems solved by technology

First, the current research on the optimization of multi-layer thermal insulation and variable density is mainly carried out around the multi-layer thermal insulation structure. At present, there is no research on the optimization of composite variable-density multi-layer thermal insulation structure; There are few studies on variable density optimization of structures, and the research on variable density optimization is mainly carried out around liquid hydrogen and liquid nitrogen storage tanks

Liquid helium is the liquid with the lowest temperature at present, its critical temperature is as low as 5.15K, and its boiling point is as low as 4.2K, which is much lower than cryogenic liquids such as LNG and liquid nitrogen, and even lower than liquid hydrogen. The sensitivity to heat leakage is the highest, and the evaporation loss and storage and transportation safety problems caused by heat leakage are the most serious. Therefore, the demand for variable density optimization research on composite multi-layer insulation for liquid helium storage tanks is extremely urgent, but there is almost no research on liquid helium storage tanks. Literature Report on the Optimization of Tank Variable Density

Third, the existing research on variable density optimization mainly adopts the orthogonal experiment method or artificially sets the termination conditions of variable density optimization, resulting in suboptimal results of variable density optimization, that is, the thermal insulation performance of storage tanks can be further improved

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