KR920010528B1 - Method for deciding the amount of absorbing heat of the heat furnace - Google Patents

Method for deciding the amount of absorbing heat of the heat furnace Download PDF

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KR920010528B1
KR920010528B1 KR1019890020415A KR890020415A KR920010528B1 KR 920010528 B1 KR920010528 B1 KR 920010528B1 KR 1019890020415 A KR1019890020415 A KR 1019890020415A KR 890020415 A KR890020415 A KR 890020415A KR 920010528 B1 KR920010528 B1 KR 920010528B1
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temperature
steel
furnace
equation
absorption rate
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KR1019890020415A
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KR910012300A (en
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김기홍
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포항종합제철 주식회사
정명식
재단법인 산업과학기술연구소
백덕현
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D11/00—Process control or regulation for heat treatments

Abstract

(1) measuring actual temperature (Tn-m) of the inside of steel and atmosphere temperature (Tg) of heating furnace, (2) deducing pre-estimated temperature (T1) of the sample volume with the temperature distribution estimating equation, (3) calculating and minimizing evaluated function (P) as an equations of (I) and (II), (4) calculating the total thermal absorption ratio of heating furnace (φCG) by an equation of (III) [Where qK,; = heat flow rate, Ts, i = surface temperature of steel .

Description

가열로의 총괄열흡수율 결정방법Determination method of overall heat absorption rate of furnace

제1a도는 데이터로거의 위치를 나타내는 개략도, (b)도는 데이터로거를 확대한 (a)도의 요부확대도, (c)도는 측온점위치를 나타내는 개략도.1A is a schematic diagram showing the position of the data logger, (b) is an enlarged view of the main part of (a) in which the data logger is enlarged, and (c) is a schematic diagram showing the temperature measuring point position.

제2도는 강재온도분포예측을 위한 대표부피의 선정을 나타내는 개략도.2 is a schematic diagram showing selection of representative volume for predicting steel temperature distribution.

제3도는 스키드부에 대한 재료시간(분)에 따른 온도변화를 나타내는 그래프.3 is a graph showing the temperature change according to the material time (minutes) for the skid portion.

제4도는 비스키드부에 대한 재로시간(분)에 따른 온도변화를 나타내는 그래프.4 is a graph showing the temperature change according to the idle time (minutes) for the non-skid part.

제5도는 스키드부에 대한 재로시간(분)에 따른 총괄열흡수율변화를 나타내는 그래프.5 is a graph showing the change in the overall heat absorption rate according to the idle time (minutes) for the skid portion.

제6도는 비스키드부에 대한 재로시간(분)에 대한 총괄열흡수율변화를 나타내는 그래프.6 is a graph showing the change in the overall heat absorption rate for the idle time (minutes) for the non-skid part.

제7도는 스키드부에 대한 재로시간(분)에 따른 온도편차를 나타내는 그래프.7 is a graph showing the temperature deviation according to the idle time (minutes) for the skid portion.

제8도는 비스키드부에 대한 재로시간(분)에 따른 온도편차를 나타내는 그래프.8 is a graph showing a temperature deviation with respect to minutes of non-skid parts.

본 발명은 강재를 가열할 경우에 강재의 내부온도를 정확하게 예측하기 위한 강제표면의 열유속을 결정하는 방법에 관한 것으로서, 보다 상세하게는, 강재표면의 열유속을 결정하기 위하여 가열로의 총괄열흡수율을 결정하는 방법에 관한 것이다.The present invention relates to a method of determining the heat flux of the steel surface for accurately predicting the internal temperature of the steel when the steel is heated, and more particularly, to determine the heat flux of the heating furnace to determine the heat flux of the steel surface It is about how to decide.

일반적으로, 가열로에서 강재의 내부온도분포를 예측하는 방법은 강재의 온도를 직접 측정하지 않을 경우, 분위기온도와 강재표면의 열흡수율을 이용하여 하기식 1)과 같은 프리에 열전도방정식을 풀어서 내부온도를 예측하는 방법이다.In general, the method of estimating the internal temperature distribution of steel in the heating furnace is to solve the internal temperature by solving the thermal conductivity equation in the following equation 1) by using the ambient temperature and the heat absorption of the steel surface when the temperature of the steel is not measured directly. How to predict.

Figure kpo00002
Figure kpo00002

여기서, ρ : 강재밀도, CP: 강재비열, T : 온도, T : 시간, (x, y, z) : 두께, 길이, 폭방향변위, λ : 열전도를 나타낸다.Where ρ: steel density, C P : steel specific heat, T: temperature, T: time, (x, y, z): thickness, length, widthwise displacement, λ: thermal conductivity.

즉, 이 방법은 식(1)의 경계조건과 초기조건이 주어지면 식을 풀어서 내부온도를 예측하는 법이다. 이때 경계조건으로 제2도와 같이 두께방향으로의 강제내부 온도예측을 위한 대표부피를 고려하면 다음과 같은 식들로 상기 식(1)의 경계조건과 초기조건을 나타낼 수 있다.In other words, this method predicts the internal temperature by solving the equation given the boundary and initial conditions of Eq. (1). In this case, considering the representative volume for the forced internal temperature prediction in the thickness direction as shown in FIG. 2, the boundary condition and initial condition of Equation (1) can be represented as follows.

Figure kpo00003
Figure kpo00003

여기서 H는 강재의 두께를 나타낸다. 그러나, 이러한 방법은 로내상황이 시시각각 변하기 때문에 온도 및 가스 성분, 가스층두께등의 함수인 열흡수율이 계속적으로 달라져 정확한 표면열유속결정이 어렵고 따라서 정확한 강재내부온도가 구해지기는 더욱 어렵다.Where H represents the thickness of the steel. However, in this method, since the furnace conditions change from time to time, the heat absorption rate, which is a function of temperature, gas component, gas layer thickness, etc., is continuously changed, making it difficult to determine accurate surface heat flux, and therefore, it is more difficult to obtain accurate steel internal temperature.

그렇기 때문에 본 발명에서는 좀더 정확한 강재내부온도를 알기위해 직접 강재내 온도를 측정하고 측정된 강재내부에 온도분포를 만족시키는 표면열유속을 결정하는 방법을 찾고자 하였다.Therefore, in the present invention, in order to find a more accurate internal temperature of the steel, the present invention was to find a method of directly measuring the temperature in the steel and determining the surface heat flux satisfying the temperature distribution in the measured steel.

또한, 구해진 표면열유속의 신뢰성을 검증하기 위해 실측된 강재내 온도분포와 구해진 표면열유속을 식(1-1)-(1-4)의 경계조건에 대입하고 이를 이용하여 상기 식(1)을 푼 결과를 비교하였다.In addition, in order to verify the reliability of the obtained surface heat flux, the measured temperature distribution and the obtained surface heat flux are substituted into the boundary conditions of equations (1-1) to (1-4), and the equation (1) is solved. The results were compared.

총괄열흡수율은 가열로의 형상, 분위기온도, 가스조성등에 따른 강재표면으로의 복사 및 대류에 의해 유입되는 열량의 흡수율정도를 나타내는 지표로서 강재의 내부온도를 직접 측정하지 않고서는 결정이 불가능한 인자이며, 강재의 로내위치 및 분위기등의 상황에 따라 시시각각 변한다.The overall heat absorption rate is an index that indicates the degree of absorption rate of heat input by radiation and convection to the steel surface according to the shape of the furnace, atmosphere temperature, gas composition, etc., and cannot be determined without directly measuring the internal temperature of the steel. As time goes by, the location and atmosphere of the steel are changed.

이러한 총괄열흡수율을 결정하기 위해서는 강재내 온도분포를 측정하여 알고 이 측정된 온도분포를 만족시키는 표면(상, 하)의 열유속을 결정하는 것이다. 이러한 표면열유속을 본 발명에 따라 결정하는 방법에 대하여 상세히 설명하면 아래와 같다.In order to determine the overall heat absorption rate, the temperature distribution in the steel is measured and the heat flux of the surface (upper and lower) satisfying the measured temperature distribution is determined. Hereinafter, the method for determining the surface heat flux according to the present invention will be described in detail.

1) 먼저 강재내부의 온도

Figure kpo00004
분포를 측정한다. 이때, 내부 측정점은 가능한한 수채해석적으로 풀기위해 정한 절점(node)과 유사한 위치에 정한다. 가열로(1)내의 강재(2)내부 온도측정방법은 제1a도 및 제1b도와 같이 설치하고 온도이력은 내열데이터로거(3)를 이용하여 받은 다음 로밖으로 강재(2)가 추출된 후 데이터로거의 메모리기판을 온도이력 독출장치에 걸어서 온도를 알 수 있다.1) First, the temperature inside the steel
Figure kpo00004
Measure the distribution. At this time, the internal measurement point should be located at the position similar to the node defined for solving the problem as possible. The internal temperature measurement method of the steel (2) in the furnace (1) is installed as shown in Figs. 1a and 1b, and the temperature history is received using the heat-resistant data logger (3), and then the steel (2) is extracted out of the furnace. The temperature can be obtained by hanging the logger's memory board on the temperature history reader.

제1b도에서, 3a는 냉각장치, 3b는 데이터기억소자, 3c는 수증기 증발구, 3d는 단연재, 3e는 열전대, 3f는 측온점을 나타낸다. 제1c도는 내부측정점의 위치를 나타낸다.In FIG. 1B, 3a represents a cooling device, 3b represents a data storage element, 3c represents a vapor evaporation port, 3d represents a short material, 3e represents a thermocouple, and 3f represents a temperature measurement point. 1C shows the position of the internal measurement point.

2) 워킹빔(walking beam) 형식의 가열로에서 강재가 가열되는 경우에 강재가 지지되는 부분(skid)과 지지되지 않는 부분(non-skid)을 고려하여 강재내부온도분포예측을 위한 대표부피(control volume)를 제2도의 빗금친 부분으로 하였다. 이러한 대표부피의 두께방향으로의 양경계면에서의 예측온도(T1)를 가열로 연소제어시 사용되는 강재온도분포예측수식 모델의 차분방정식에 의해 1차원적으로 추정한다.2) Representative volume for predicting the temperature distribution inside the steel considering the skid and non-skid parts of the steel when the steel is heated in a walking beam type furnace ( control volume) was the hatched portion of FIG. The predicted temperature (T 1 ) at the two boundary surfaces in the thickness direction of the representative volume is estimated one-dimensionally by the differential equation of the steel temperature distribution prediction equation model used in the furnace combustion control.

예를들면, 강재내부 결점을 두께방향 5점으로 할 때 강재온도분포예측수식 모델의 차분방정식은 하기식(2)와 같다.For example, when the steel internal defect is 5 points in the thickness direction, the differential equation of the steel temperature distribution prediction equation model is given by the following equation (2).

Figure kpo00005
Figure kpo00005

여기서, D : 절점사이거리, △t : 시간증분, T

Figure kpo00006
: 시간 t에서의 강재온도. T
Figure kpo00007
-1: 시간t+△t에서의 강재온도, λ : 강재의 열전도도, r : 강재의 밀도Where D is the distance between nodes, Δt is the time increment, T
Figure kpo00006
: Steel temperature at time t. T
Figure kpo00007
-1 : steel temperature at time t + Δt, λ: thermal conductivity of steel, r: density of steel

3) 강재온도 측온시 측정점과 실제 수식모델에서 계산시 사용되는 위치가 다르기 때문에 모델점의 온도 즉, 상기 차분방정식에서 구한 예측온도(T1)를 이용하여 측온점의 온도 즉, 추정측온온도(Tn m)를 다음과 같이 나타낸다.3) Since the measurement point for steel temperature measurement and the position used for calculation in the actual mathematical model are different, the temperature of the temperature measurement point, that is, the estimated measurement temperature (using the predicted temperature T 1 obtained from the differential equation) T n m ) is expressed as follows.

Figure kpo00008
Figure kpo00008

단, Tn m: 추정측온온도Where T n m : estimated temperature

T1: 모델계산시 결점온도(예측온도)T 1 : Defective temperature (predicted temperature) in model calculation

Fmi: 보정인자F mi : correction factor

이때, Fmi의 결점은 아래와 같이 행한다.At this time, the defect of F mi is performed as follows.

우선 강재내부의 온도분포를 2차함수(T(x)=ax2+bx+c)로 가정하고 상부표면(x=H/2), 중심(x=0), 하부표면(x=2H/2)에서의 온도를 T(H/2)=T1, T(0)=T3, T(-H/2)=T5라하면 계수 a, b, c는 각각 a=2(T1-2T3+T5)/H, b=(T1-T5)/H, C=T3가 된다. 따라서 강재내 온도분포함수는 측온실험시 측정점의 위치를 x1 m, x2 m, x3 m, x4 m라 하면,First, the temperature distribution inside the steel is assumed to be a second function (T (x) = ax 2 + bx + c) and the upper surface (x = H / 2), center (x = 0), and lower surface (x = 2H / If the temperature at 2) is T (H / 2) = T 1 , T (0) = T 3 , T (-H / 2) = T 5 , the coefficients a, b, and c are respectively a = 2 (T 1 -2T 3 + T 5 ) / H, b = (T 1 -T 5 ) / H, C = T 3 Therefore, if the temperature distribution function in steel is x 1 m , x 2 m , x 3 m , x 4 m ,

Figure kpo00009
Figure kpo00009

식 3)과 4)를 비교하면,Comparing Equations 3) and 4),

Figure kpo00010
Figure kpo00010

4) 3)과정에서 추정측정온도(Tn m)와 실제측정온도

Figure kpo00011
와의 편차제곱을 평가함수 P로 정의하고 P를 최소로 하는 조건을 구비한다.4) Estimated measuring temperature (T n m ) and actual measuring temperature
Figure kpo00011
The deviation square with is defined as the evaluation function P, and the condition that minimizes P is provided.

Figure kpo00012
Figure kpo00012

단, 1은 실측점의 개수1 is the number of actual points

평가함수가 최소로 되는 조건은 다음과 같다.The conditions under which the evaluation function is minimum are as follows.

Figure kpo00013
Figure kpo00013

단, q는 강재표면 열유속(heat flux)이다.Q is the heat flux of the steel surface.

상기 식(3)을 상기 식(7)에 대입하여 정리하면,Substituting the above formula (3) into the above formula (7),

Figure kpo00014
Figure kpo00014

이 된다.Becomes

5) 상기식 (2)와 상기식(8)을 조립한 식을 쓰면 식(9)와 같은 행렬식으로 쓸 수 있다.5) If the equation (2) and the equation (8) are assembled, the determinant can be written as the equation (9).

Figure kpo00015
Figure kpo00015

상기 식(9)을 풀면 T(i=1, 5) 및 q(k=1, 2)가 구해진다. 이때 q는 강재내부온도분포인 T를 만족시키는 상하표면 열유속이다.Solving the above formula (9), T (i = 1, 5) and q (k = 1, 2) are obtained. Q is the upper and lower surface heat flux satisfying T, the steel internal temperature distribution.

6) 식(9)의 계산에 사용되는 강도(

Figure kpo00016
T1/
Figure kpo00017
qk), 열유속변화에 대한 강재내부특정절점에서의 온도변화의 비는 상기 식(2)를 q(k=1, 2)로 편미분하여 구한다.6) the strength used in the calculation of equation (9)
Figure kpo00016
T 1 /
Figure kpo00017
q k ), the ratio of the temperature change at the specific internal point of the steel to the heat flux change is obtained by partial derivative of equation (2) with q (k = 1, 2).

Figure kpo00018
Figure kpo00018

여기서 k가 1인 경우에 A는 상기식(2)의 계수행렬과 동일하며 T는 (T1, T2, T3, T4, T5)이고, D는 (2D/λ1, 0, 0, 0, 0)T이며, k가 2일 때는 D가 (0, 0, 0, 0, 2D/λ5)T이 된다.Where k is 1, A is the same as the coefficient matrix of Equation (2), T is (T 1 , T 2 , T 3 , T 4 , T 5 ), and D is (2D / λ 1 , 0, 0, 0, 0) T , and when k is 2, D becomes (0, 0, 0, 0, 2D / λ 5 ) T.

7) 1)-6)의 과정을 거쳐 구해진 qk,j(k=1 (상), 2(하), j=1(스키드부), 2(비스키드부))와 강재표면온도 Ts,i(T1,1, T1,2, T5,1, T5,2)와 로내 강재위치에서의 분위기온도(Tg)를 이용하여 가열로 고유계수인 총괄열흡수율을 구한다.7) q k , j (k = 1 (top), 2 (bottom), j = 1 (skid part), 2 (non-skid part)) obtained through the process 1) -6) and steel surface temperature T s The overall heat absorption rate, which is the intrinsic coefficient of the heating furnace, is determined using , i (T 1,1 , T 1,2 , T 5,1 , T 5,2 ) and the ambient temperature (Tg) at the furnace steel position.

Figure kpo00019
Figure kpo00019

8) 7)에서 구해진 총괄열흡수율은 로위치에 따라 시시각각 변하기 때문에로 사양 및 로내 분위기온도측정용 열전대위치에 따라 구간을 나누어 보통은 구해진다. 일반적인 경우 예열대, 가열대, 균열대로 나누어 총괄열흡수율이 구해진다.8) Since the total heat absorption rate obtained in 7) changes from time to time depending on the furnace location, it is usually obtained by dividing the interval according to the specifications and the thermocouple position for measuring the atmosphere temperature in the furnace. In general, the overall heat absorption is obtained by dividing the preheating zone, the heating zone, and the crack.

1)에서 8)의 과정을 거쳐 구해진 총괄열흡수율(øCG)을 이용하여 로내 분위기온도 및 가열 로내 강재의 체류시간변화에 따른 강재내부의 온도분포를 구할 수 있다. 실제로 총괄열흡수율은 가열로의 최적연소를 위해 특정강재의 승온곡선을 얻기 위해서는 필수적으로 알아야하는 인자이다. 일단 로 고유의 총괄열흡수율이 구해지면 대폭적인 조업조건 분위기온도, 강재크기, 체류시간등)의 변동이 없는 한 또 다른 강재의 온도분포를 예측하는 것이 가능해지기 때문에 가열로 연소제어를 위해서나 가열로의 기타 성능해석을 위해서도 총괄열흡수율을 결정한다는 것은 매우 중요한 일인 것이다. 앞의 과정 3)에서 강재내 온도분포를 2차로 가정하여 보정인자를 구했으나 실제 측정된 강재내부 온도분포가 2차식 이외의 즉, 3차 혹은 4차식에 잘맞을 경우에도 보정인자를 달리 구하는 식을 전재시킬 수 있다. 이 경우에는 내부온도분포를 3차식으로 가정할때는 두께방향실측점의 개수가 최소한 4점 이상, 4차식일 경우에는 5점 이상이 필요하다.Using the total heat absorption rate (ø CG ) obtained through the process 1) to 8), the temperature distribution inside the steel according to the change in the atmosphere temperature in the furnace and the residence time of the steel in the heating furnace can be obtained. In fact, the overall heat absorption rate is an essential factor to obtain the temperature rise curve of a specific steel for optimum combustion of the furnace. Once the intrinsic overall heat absorption rate of the furnace is obtained, it is possible to predict the temperature distribution of another steel as long as there are no significant changes in operating conditions, such as atmospheric temperature, steel size, residence time, etc. It is also very important to determine the overall heat absorption for other performance analysis. In the above process 3), the correction factor was obtained by assuming that the temperature distribution in the steel was second, but the correction factor was calculated differently even when the actual measured internal temperature distribution fits well other than the second, that is, the third or fourth equation. Can be reprinted. In this case, if the internal temperature distribution is assumed to be cubic, at least 4 points in thickness direction are required, and at least 5 in cubic.

따라서 강재내 실측온도분포의 형태를 보고 내부온도분포곡선을 2, 3차식 중 어느하나를 가정하여 앞의 상세설명 과정 1)에서 8)을 거쳐 총괄열흡수율을 결정할 수도 있다.Therefore, it is also possible to determine the overall heat absorption rate through the above detailed process 1) to 8) by looking at the shape of the measured temperature distribution in the steel and assuming that the internal temperature distribution curve is either 2nd or 3rd order.

이하, 실시예를 통하여 본 발명을 설명한다.Hereinafter, the present invention will be described through examples.

[실시예]EXAMPLE

예열대, 가열대, 균열대로 이루어진 유효장 36m인 워킹빔식 강재 가열로에서 제1도와 같이 내열데이터로거를 강재위에 장착시켜 장개의 내부온도

Figure kpo00020
를 측정하였다. 다음에 측정된 온도이력을 이용하여 본 발명에 따라 가열로의 고유한 값인 총괄열흡수율을 구하였다.In the working beam type steel furnace, which has an effective length of 36m consisting of preheating table, heating table, and cracking bar, the heat resistant data logger is mounted on the steel as shown in Fig.
Figure kpo00020
Was measured. Next, using the measured temperature history, the overall heat absorption rate, which is a unique value of the heating furnace, was obtained according to the present invention.

즉, 제3도는 제1c도에서와 같은 강재의 측온위치에서 스키드부의 온도를 실측한 결과(Tn m)를 이용하여, 강재내 온도분포를 2차 함수라고 가정하고 나타낸 계산절점의 온도변화그래프이다.That is, FIG. 3 is a graph of temperature change of the calculated node assuming that the temperature distribution in the steel is a quadratic function using the result (T n m ) of the temperature of the skid at the temperature measurement position of the steel as in FIG. 1c. to be.

제4도는 비스키드부에 대한 결과이다. 분위기온도는 실측가열로의 각대 제어용 열전대의 온도로 하였다.4 is the result for the non-skid part. Atmosphere temperature was made into the temperature of each thermocouple for control of a measurement heating furnace.

제5도 및 제6도는 본 발명에 의한 방법으로 강재의 로내위치에 따른 스키드부와 비스키드부의 상, 하표면에서의 총괄열흡수율을 구한 결과를 나타낸다.5 and 6 show the results of calculating the overall heat absorption at the upper and lower surfaces of the skid part and the non-skid part according to the furnace position of the steel by the method according to the present invention.

제7도 및 제8도는 위에서 구한 총괄열흡수율을 이용하여 열유속을 구하고 이를 경계조건으로하여 상기 식(1)의 차분방정식(2)을 풀어 예측한 강재온도분포와 실체측온온도

Figure kpo00021
와의 편차를 나타낸 결과로서, 약 5℃ 정도의 편차로 상당히 잘 일치함을 보여주고 있다.7 and 8 show the steel temperature distribution and the actual temperature measured by calculating the heat flux using the overall heat absorption rate obtained above and solving the differential equation (2) of Eq.
Figure kpo00021
As a result of the deviation from and, it shows a good agreement with the deviation of about 5 ° C.

이러한 실시예의 결과로보아 본 발명의 방법으로 총괄열흡수율을 구하고 이를 이용하여 가열로내 온도분포를 예측한다면 강재의 온도분포예측정도를 상당히 향상시킬 수 있을 것으로 예상되며 또한 가열로 연소제어의 기본인 강재온도예측을 정확하게 함에 의하여 가열로의 에너지절감은 물론 판 품질의 향상에도 기여하리라 여겨진다.As a result of this embodiment, if the overall heat absorption rate is calculated by the method of the present invention and the temperature distribution in the furnace is predicted by using the method of the present invention, it is expected that the degree of measurement of the temperature distribution of the steel can be significantly improved. Precise steel temperature prediction is expected to contribute not only to energy saving of furnace but also to improvement of plate quality.

Claims (1)

가열로의 총괄열흡수율에 의해 강재표면의 열유속을 구하고, 이 열유속을 이용하여 가열로내의 강재내부온도를 추정하는데 있어서, 상기 가열로내에 위치되어 있는 강재내부의 실제측온도
Figure kpo00022
및 가열로내 분위기온도(Tg)를 측정하는 단계 ; 강재내부 온도분포를 예측하기 위한 대표부피에 대한 두께방향으로의 양계면에서의 예측온도(Ti)를 가열로연소제어시 사용되는 강재온도분포예측수식 모델의 차분방정식에 의해 1차원적으로 추정하는 단계 ; 가열로 연소제어시 사용되는 강재온도분포예측수식 모델에 있어 추정측온온도(Tn m)를 상기 단계에서 구한 예측온도(Ti) 및 강재온도측온시 측정점과 실제수식모델에서 계산시 사용되는 모델점의 위치차이에 기인한 온도편차를 보정하기 위한 보정인자(Fmi)에 의해 하기식(8)과 같이 구하는 단계 ;The heat flux of the steel surface is calculated from the overall heat absorption rate of the furnace, and the actual temperature inside the steel located in the furnace is used to estimate the internal steel temperature in the furnace using the heat flux.
Figure kpo00022
And measuring the atmosphere temperature (Tg) in the furnace; Estimated temperature (T i ) at both interfaces in the thickness direction with respect to the representative volume for predicting the internal temperature distribution in steel by one-dimensional differential equation of steel temperature distribution prediction equation used in furnace combustion control Doing; Estimated in the steel material temperature distribution predictive mathematical expression model used in the combustion control the furnace temperature measuring temperature (T n m) the predicted temperature obtained in step (T i) and the steel temperature model used in the calculation from the temperature detecting when the measurement point and the actual mathematical model Obtaining by the correction factor (F mi ) for correcting the temperature deviation caused by the positional difference of the point as shown in the following formula (8);
Figure kpo00023
Figure kpo00023
 하기식(6)과 같이 상기 단계에서 구한 추정측온온도(Tn m)와 실제측온온도
Figure kpo00024
와의 편차제곱으로 표시되어지는 평가함수(P)를 최소로하는 조건을 하기식(8)과 같이 구하는 단계 ;Estimated measured temperature (T n m ) and actual measured temperature obtained in the above step as shown in Equation (6)
Figure kpo00024
Obtaining a condition for minimizing the evaluation function P expressed by the square of the deviation as shown in Equation (8);
Figure kpo00025
Figure kpo00025
 상기한 가열로 연소제어시 사용되는 강재온도분포예측수식 모델의 차분방정식과 상기한 평가함수의 최소화 조건식(8)을 조합한 행렬식에 의해 강재온도(Ti) 및 강재 상, 하표면부의 열유속(qk,j)을 구하는 단계 ; 및 상기에서 측정된 가열로내 분위기온도(Tg), 및 상기에서 구한 강재 상, 하표면부의 열유속(qk,j) 및 강재온도(Ti) 중 강재표면온도(Ts,i)를 하기식(11),The steel temperature (T i ) and the heat flux of the upper and lower surface parts of the steel are determined by a matrix equation combining the differential equation of the steel temperature distribution prediction equation model used for the combustion furnace control described above and the minimization condition equation (8) described above. q k, j ); And the steel surface temperature (T s, i ) of the atmosphere temperature (Tg) measured in the above, and the heat flux (q k, j ) and the steel temperature (T i ) of the steel phase, the lower surface portion obtained above. (11)
Figure kpo00026
Figure kpo00026
 에 대입하여 총괄열흡수율(øCG)를 구하는 단계를 포함하여 구성됨을 특징으로 하는 가열로의 총괄열흡수율 결정방법.Obtaining the total heat absorption rate (ø CG ) by substituting to the total heat absorption rate determination method of the furnace, characterized in that it comprises a.
KR1019890020415A 1989-12-30 1989-12-30 Method for deciding the amount of absorbing heat of the heat furnace KR920010528B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100689153B1 (en) * 2005-10-13 2007-03-02 주식회사 포스코 Method for estimating temperature of slab in heating furnace
KR100936357B1 (en) * 2002-12-24 2010-01-12 재단법인 포항산업과학연구원 Decision method of the position and the quantity of the temperature sensor and of the heating zone in a reheating furnace
KR100957914B1 (en) * 2008-07-02 2010-05-13 주식회사 포스코 Method for lessening scale loss ratio in hot rolling process

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100936357B1 (en) * 2002-12-24 2010-01-12 재단법인 포항산업과학연구원 Decision method of the position and the quantity of the temperature sensor and of the heating zone in a reheating furnace
KR100689153B1 (en) * 2005-10-13 2007-03-02 주식회사 포스코 Method for estimating temperature of slab in heating furnace
KR100957914B1 (en) * 2008-07-02 2010-05-13 주식회사 포스코 Method for lessening scale loss ratio in hot rolling process

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