Method and system for measuring flow of working medium in water cooled wall tube online

Abstract

The invention discloses a method and system for measuring the flow of a working medium in a water cooled wall tube online. The method comprises the implementation steps that with respects to two elevation positions on the water cooled wall tube, temperatures of a tube external wall middle point A on the back fire side, a fin root point B and a fin middle point C are acquired, and a temperature difference delta TAB and a temperature difference delta TAC are calculated; the heat flux density q and a convective heat-transfer coefficient alpha are solved based on a relation f1(alpha, q) and a relation f2 (alpha, q); then the heat flux density q and the convective heat-transfer coefficient alpha are substituted into a relation fv(alpha, q), a temperature difference delta TAV is solved, the meanwall temperature TV of the tube internal wall in the peripheral direction and the temperature TS of the working medium in the water cooled wall tube are calculated, and thus the temperatures TS1 andTS2 of the tube interior working medium at different elevation positions are obtained; and finally, the flow of the working medium in the water cooled wall tube is obtained after calculation accordingto a formula (1). On-line measurement on the flow of the working medium in the membrane type water wall tube of a utility boiler can be realized, and the method and the system have an important guiding significance in anticipating heat transfer deterioration of the water cooled wall tube and taking measures in advance to prevent tube bursting.

Description

technical field [0001] The invention relates to a boiler detection technology, in particular to an online measurement method and system for working medium flow in a water-cooled wall tube. Background technique [0002] The water-cooled wall is one of the main components of the boiler. Its function is to transfer the heat energy generated by the combustion of fuel in the furnace to the working medium in the water-cooled wall tube. Therefore, the working process of the water-cooled wall is a process of absorbing heat from the furnace and releasing heat to the working medium in the tube. The working temperature of the process depends on the balance of endothermic and exothermic. Limited by the material, the water-cooled wall has a maximum allowable working temperature. When the heat absorption and heat release of the water-cooled wall reach a balance, and the temperature in the equilibrium state does not exceed the maximum allowable working temperature, the water-cooled wall is...

AI Technical Summary

Problems solved by technology

However, in the face of the complex and changeable working conditions in the actual operation of the boiler, the current design method is still difficult to accurately match the working fluid flow and heat load under different working conditions

Due to the change of the resistance characteristics of the water wall or the change of the working conditions, the over-temperature tube explosion accidents caused by the mismatch between the flow rate of the working fluid and the regional heat load occur from time to time, which seriously affects the safe, stable and economical operation of the boiler.

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