RU1828545C - Method of determination of fusion characteristics - Google Patents

Abstract

SUMMARY OF THE INVENTION: Three heat-absorbing elements with the thermophysical characteristics of the materials from which they are made, satisfying the ratio ai an-1, where ai is the thermal diffusivity of the 1st element, are introduced into the controlled melt zone. Using temperature sensors, the temperatures of the heat-absorbing surfaces of the elements and the temperatures are measured at least at two points along the heat flux q through the heat-receiving elements. By jointly processing the temperature measurements, the melt temperature, the heat transfer coefficient from the melt to the heat-receiving elements, and the heat release intensity in the melt zone are determined. In order to provide a one-dimensional heat flux through the heat-absorbing elements, they are surrounded by thermal insulation.

Description

No.

WITH

The invention relates to physicochemical analysis of materials, in particular to methods for studying materials using thermal means.

The chain of the invention is to increase the accuracy, expand the range of application and functionality of the method in the field of non-stationary processes due to the complex simultaneous determination of the temperature of the melt T (t), heat transfer coefficients o (T) from the melt to heat-absorbing elements and the intensity of heat release A q (g) from the interaction of heat-receiving elements with the melt.

The drawing shows a thermal diagram of a device for implementing the proposed method.

The introduction of the melt of heat-receiving elements 2, 3, 4 into the controlled local zone 1 is shown. To measure temperatures along the heat flux (q) in heat-receiving elements 2, 3, 4, they are equipped with temperature sensors 5. In order to create a one-dimensional heat flow through heat-receiving elements 2, 3, 4, they are placed in a heat-shielding material 6 with a low coefficient of thermal conductivity (for example, ceramics).

The method includes the following operations. In the controlled zone 1 of the melt, three heat-sensing elements 2, 3, 4 are introduced with the thermophysical characteristics of the materials from which they are made, satisfying the ratio

ai-i. (1)

In the implemented example, heat-absorbing elements from various grades of ceramics were used, in the process of

N3 00 SL

Јь

SL

with

the preparation of which thermal sensors 5 were installed.

The heat flux from the melt 1 is transferred to the heat-receiving elements 2, 3,4 and then passes through them through heat conduction. As a result of the fact that the thermal characteristics of the materials from which the heat-receiving elements 2, 3, 4 are made are different, the densities of heat fluxes qi diverted from such elements will also be different. Due to the difference in heat fluxes, the temperature T | the outer surfaces of the heat-receiving elements 2, 3, 4 will also be different.

In this case, we can write a closed, well-conditioned system of equations for the heat transfer process of the outer surface of heat-receiving elements

qi (r) “SPRP-ry-TO + Dchf, 1 1,2,3. (2)

This system of equations is a system of three equations with three unknowns a (T), Tp (r), D q (r).

Solving the system of equations (2) with respect to the unknown a (T), Tp (t), A q (t), we can obtain

Q.m-llq c + t "O- tGf-tnmSt) 1 (J)

T -T ;; g:;:; g .. (g) -F (t)

(TM (r) -Ti (r)).

After immersing the heat-receiving elements 2, 3, 4 in the controlled melt zone, the temperatures Ti of the elements 2, 3, 4 and temperatures are measured at least at two points along the heat flux q through the heat-receiving elements 2,3.4.

According to the results of temperature measurements, the heat flux qi (r) extracted from the heat-removing elements is calculated from the solution of the inverse heat conduction problem, the formulation of which for the case considered has the form

a, c ,, Th dti (x.r) -J-agtl3t (x-r)

qiCi (ri) eg - xlM Oax

Xi Ј a, bt, r € (0,

Ti (X, 0) -fi (X), Xe {a,

Ti (Xj, r) f I, J (T}, r € (0,

(.) 4CT,

where q, C (T). A (G) - density, heat capacity and thermal conductivity of the material of the heat-receiving element;

T is the temperature; t is time;

X is the coordinate of the length of the heat sink element;

Xj is the coordinate of the temperature measuring point;

I 1, 2, 3 - the number of heat-absorbing elements;

j 1k is the number of measurement points

0 temperature.

Then, using the dependences (3) - (5), the desired parameters are determined.

Thus, by jointly processing the temperature measurements, it5 conducts a comprehensive simultaneous determination of the heat transfer coefficients from the melt to the heat-receiving elements, the melt temperature, and the intensity of heat release from the interaction

0 heat-receiving elements with a melt, which eliminates the error inherent in the known method (for example, a change in temperature at the interface the surface of the heat-receiving

5 elements - melt) and increase the accuracy of the method. The error of the results obtained in this case is up to the error level of direct temperature measurements.

0 At the same time, it becomes possible to carry out measurements regardless of the degree of non-stationarity of the investigated process, which extends the range of use of the method,

5 In addition, due to the complex simultaneous determination along with the melt temperature of the parameters determining the process of thermal interaction in the controlled zone, the functional capabilities of the method for identifying the process under study are expanded.

Thus, the accuracy is improved, the range of use and functionality of the method is expanded.

5 The estimated economic effect of the proposed method, allowing with a high degree of accuracy to carry out integrated operational control of the characteristics of the melt, is expressed in

0 reducing production costs associated with the production and use of melts, improving the quality of the products, and a percentage reduction in defective products.

Claims (1)

5 Claims A method for determining melt characteristics is as follows. that heat-sensing elements with temperature sensors are introduced into the controlled melt zone, the temperature is measured of the melt and judges on it about the characteristics of the melt, characterized in that, in order to increase accuracy, expand the range of use and functionality of the method in the field of non-stationary processes due to the complex simultaneous determination of the temperature of the melt Tp (t), heat transfer coefficients a (T ) from the melt to the heat-receiving elements and the intensity of heat release Aq (t) from the interaction of the heat-receiving elements with the melt, three heat-receiving elements from the telophysis are introduced into the controlled zone the physical characteristics of the materials from which they are made, satisfying the ratio ai en-i. where ai is the thermal diffusivity of the 1st element, the temperatures of the heat-absorbing surfaces of the elements and the temperatures are measured at least at two points along the heat flux through the heat-absorbing elements, local temperature is determined by the results of temperature measurements 2 4 And 3 the heat fluxes qi (t) removed by heat-absorbing elements determine the heat transfer coefficients o (T) from the melt to the heat-receiving elements, the melt temperature Tp (t) and the heat release rate Aq (t) from the interaction of the heat-receiving elements with the melt according to the formulas n-1 $ & Ј $ 1 w-T a i; g: qT;:; {g.-. Aq (r)) (TM (r) -Ti (r) j. where Th (t), Ti (t), Ti + i (z) and dy (t), qi (g), qi-n (t) are the temperatures and heat fluxes of the heat-receiving surfaces of the heat-receiving elements; F is the heat-absorbing surface area, and the melt characteristics are judged by them.