A Method for Measuring the Heat Flux and Temperature of the Hot Surface of the Crystallizer

Abstract

The invention relates to a method for measuring heat flux density and temperature of a crystallizer hot surface, belonging to the technical field of continuous casting. The invention collects temperature data by reasonably installing two sets of thermocouples in the continuous casting crystallizer, and converts the collected temperature data in the crystallizer wall into heat flux density and temperature on the hot surface of the crystallizer by using the two-dimensional heat transfer inverse problem. The invention has high industrial application value, and can more accurately calculate and obtain the heat flux density and temperature of the crystallizer hot surface.

Description

technical field [0001] The invention relates to a method for measuring heat flux density and temperature of a crystallizer hot surface, belonging to the technical field of continuous casting. Background technique [0002] The calculation of heat flux density and temperature on the hot surface of the mold has an important influence on the quality control of the slab and the selection of process parameters. At present, the methods for measuring the heat flux of the continuous casting mold are: 1. Direct method, assuming that the mold wall is one-dimensional heat transfer, two thermocouples with different depths are installed in the horizontal direction, and then the heat flux is equal to the thermal conductivity × (thermocouple temperature difference / thermocouple distance). This technology has an implicit condition, that is, the thermal diffusivity of the crystallizer is infinite; it cannot accurately calculate the heat flux and temperature of the hot surface of the crystalli...

AI Technical Summary

Problems solved by technology

This technology has an implicit condition, that is, the thermal diffusivity of the crystallizer is infinite; it cannot accurately calculate the heat flux and temperature of the hot surface of the crystallizer; especially the heat flux near the liquid surface of the crystallizer, and cannot obtain accurate heat flow of the crystallizer Density, temperature; at the same time, heat flux density and temperature are greatly affected by thermocouple measurement noise

2. Inverse algorithm: 1D inverse algorithm, assuming that the crystallizer wall is one-dimensional heat transfer, ignoring the heat transfer in the height direction cannot accurately calculate the heat flux near the liquid surface of the crystallizer, and the temperature change of the crystallizer wall cannot be obtained

[Pinheiro, C.A.M., I.V.Samarasekera, J.K.Brimacomb, and B.N.Walker. Ironmaking & Steelmaking 27(1)(2000):37-54.] established a 2D heat transfer inverse problem to convert the temperature of thermocouples in the mold wall to The heat flux density of the device, using the Tikhnov regular method to calculate the inverse problem, this method has the ability to resist the thermocouple measurement noise, but it is difficult to determine the regular term and regular parameters when using it

Some other scholars (at home and abroad) have established a 2D heat transfer inverse problem, which converts the measured temperature into the heat flux of the crystallizer, but uses Beck's sequential function specification method to solve the inverse problem; this calculation is not suitable for calculating the multidimensional heat transfer inverse problem , while the ability to resist thermocouple measurement noise is not ideal

3. Assumed heat flux distribution curve-calibration method: Assume that the heat flux distribution curve is exponentially distributed (or parabolic respectively) along the casting direction, and then correct the distribution curve according to the measured temperature difference between the inlet and outlet of the crystallizer cooling water; this method It can only roughly calculate the heat transfer state of the crystallizer, and cannot obtain an accurate heat flux distribution curve, especially near the liquid level of the crystallizer, which is more distorted

4. Estimate the convective heat transfer coefficient of the cooling water tank: use the empirical formula to estimate the convective heat transfer coefficient of the crystallizer cooling water tank (or calculate the flow field of the crystallizer cooling water, and then use the convection-heat transfer boundary layer theory to calculate the crystallizer cooling water tank convective heat transfer coefficient), and then calculate the crystallizer heat flux density according to the established mathematical model; the crystallizer cooling water is turbulent in the water tank, it is difficult to calculate its instantaneous flow state, so the convective heat transfer coefficient of the cooling water tank is difficult to prepare is calculated

Images