An Approximate Measurement Method of Critical Heat Flux Used in Low Flow Velocity CHF Experiments

Abstract

The invention discloses a critical heat flux approximate measurement method for CHF experiments at low flow rates, which comprises the following steps: 1) increasing the heating power of the experiment body so that the outlet of the experiment body reaches an equilibrium state, and recording the equilibrium state data; 2) , Continue to increase the heating power until the critical boiling occurs, and record the critical data; 3), based on the equilibrium data, obtain the heat loss share, 4), obtain the critical heat flux q based on the critical data c ,Calculated as follows: In the formula, N c is the electric power applied to the experimental body at the critical moment of boiling, ξ h Indicates the thermal cycle of the channel; L h Indicates the heating length of the channel, ε c is the heat loss share of the experiment body at the moment of critical boiling; let ε c =ε(heat loss share), get The invention solves the problem in the prior art that estimating heat loss through experience leads to large measurement errors of critical heat flux density and reduces economical efficiency.

Description

technical field [0001] The invention relates to the technical field of thermal-hydraulic experiments of reactors, in particular to an approximate measurement method for critical heat flux used in CHF experiments at low flow rates. Background technique [0002] The critical heat flux condition refers to the state in which the boiling heat transfer mechanism just changes and the heat transfer coefficient suddenly drops sharply (also known as boiling crisis, boiling critical, and heat transfer deterioration). Critical Heat Flux (Critical Heat Flux, abbreviated as CHF ) refers to the value of heat flux under this working condition. This parameter characterizes the limit heat transfer capacity of the heat transfer process, so it is very important. [0003] Due to the complexity and importance of boiling criticality, CHF values ​​are still mainly obtained through experiments in engineering. During the experiment, due to air convection and thermal radiation, only part of the heat...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a method for approximate measurement of critical heat flux for CHF experiments at low flow rates, which solves the problems in the prior art that the estimation of heat loss by experience leads to large errors in the measurement of critical heat flux and reduces the economy

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