CN103995017B

CN103995017B - A kind of experimental technique measuring cyclical heat transmission coefficient

Info

Publication number: CN103995017B
Application number: CN201410139701.3A
Authority: CN
Inventors: 赵增武; 张亚竹; 胡强
Original assignee: Inner Mongolia University of Science and Technology
Current assignee: Inner Mongolia University of Science and Technology
Priority date: 2014-04-04
Filing date: 2014-04-04
Publication date: 2016-08-17
Anticipated expiration: 2034-04-04
Also published as: CN103995017A

Abstract

The invention discloses an experimental method for measuring periodic heat transfer coefficients, which is used for measuring the heat transfer coefficients of different heat transfer cycles. The device used in this experimental method includes: a rotating drum with adjustable speed, a nozzle with adjustable spray angle and spray height, a heating device placed inside the drum, a thermocouple buried in the drum body, and a temperature collecting device electrically connected to the thermoelectric. couple, and output the temperature signal of the thermocouple. The experimental method includes the establishment of mathematical model and discrete model, the calculation of heat transfer coefficient according to the inverse problem algorithm, and the verification of data according to the preset convergence value. This experimental method has the advantages of fast calculation speed and high accuracy of results, and the material to be tested can be selected according to needs, and various cooling states can be simulated to test the surface heat transfer coefficient under different cooling environments, which has a wide range of applications.

Description

An Experimental Method for Measuring Periodic Heat Transfer Coefficient

技术领域technical field

本发明涉及换热系数测定这一技术领域，具体是一种测定周期性换热系数的实验方法。The invention relates to the technical field of measuring heat transfer coefficients, in particular to an experimental method for measuring periodic heat transfer coefficients.

背景技术Background technique

在工业冷却处理过程中，换热系数的大小决定着冷却强度的大小，能够确定不同冷却水量、不同喷嘴喷射高度、不同喷射角度与换热系数之间的关系，对调节冷却强度有着重要的意义，对制定合理的冷却制度，提高产品的质量有着决定性的作用。In the industrial cooling process, the heat transfer coefficient determines the cooling intensity. It is of great significance to determine the relationship between different cooling water volumes, different nozzle spray heights, different spray angles and heat transfer coefficients, which is of great significance for adjusting the cooling intensity. , It plays a decisive role in formulating a reasonable cooling system and improving product quality.

周期性换热存在于工业生产间歇式冷却的生产流程中，即让被冷却工件一次通过排布好的冷却喷嘴，工件经过喷嘴时处于被冷却状态，当离开喷嘴喷射范围传向下一个喷嘴时处于非冷却或者回热状态。例如在连铸的二次冷却过程中，钢坯在经过二次冷却区域时，钢坯被排布好的喷嘴进行一次冷却，在喷嘴之间的非冷却区域，钢坯的液芯会向外传热，让钢坯表面回温。周期性换热有着冷却均匀，工件热应力小的特点，测试不同换热周期、不同冷却强度的换热特性对喷嘴的排布、工件传送速度、气压水压设定等都有着重要的指导意义。Periodic heat exchange exists in the production process of intermittent cooling in industrial production, that is, let the cooled workpiece pass through the arranged cooling nozzles once, and the workpiece is in a cooled state when it passes through the nozzle. In a non-cooling or reheating state. For example, in the secondary cooling process of continuous casting, when the billet passes through the secondary cooling area, the billet is cooled by the arranged nozzles, and in the non-cooling area between the nozzles, the liquid core of the billet will transfer heat outward. Let the billet surface warm up. Periodic heat exchange has the characteristics of uniform cooling and small thermal stress on the workpiece. Testing the heat exchange characteristics of different heat exchange cycles and different cooling intensities has important guiding significance for nozzle arrangement, workpiece conveying speed, air pressure and water pressure settings, etc. .

目前周期性换热系数的测定大多采用加热钢板，水平移动喷嘴的方法进行冷却，这种方法存在很大的局限性。首先由于钢板的几何特性不能很好的处理热应力，在冷却过程中很容易变形，且钢板的冷却测试次数有限，更换频繁，投入费用较高。其次该方法无法进行连续的喷射，只能往复式喷射，不符合周期性换热的喷射特点。再次钢板式移动喷嘴的方法无法自由调节的喷射角度，无法测定倾斜角度喷射的换热特性。At present, most of the periodic heat transfer coefficients are measured by heating the steel plate and moving the nozzle horizontally for cooling. This method has great limitations. First of all, because the geometric characteristics of the steel plate cannot handle thermal stress well, it is easy to deform during the cooling process, and the number of cooling tests of the steel plate is limited, frequent replacement, and high investment costs. Secondly, this method cannot carry out continuous injection, only reciprocating injection, which does not meet the injection characteristics of periodic heat exchange. Again, the steel plate type moving nozzle method cannot freely adjust the spray angle, and the heat transfer characteristics of the inclined angle spray cannot be measured.

因此，在考虑测试费用，测试调节范围，测试精度的基础上，提供一有效的测定周期性换热系数的实验方法对工业冷却生产中制定合理的冷却制度有着积极的作用。Therefore, on the basis of considering the test cost, test adjustment range and test accuracy, providing an effective experimental method for determining the periodic heat transfer coefficient has a positive effect on formulating a reasonable cooling system in industrial cooling production.

发明内容Contents of the invention

本发明需要解决的技术问题就在于克服现有技术的缺陷，提供一种测定周期性换热系数的实验方法，用来测试不同材质原料在不同周期换热下的热流量、换热系数，达到计算速度快，计算精度高的。The technical problem to be solved in the present invention is to overcome the defects of the prior art and provide an experimental method for measuring the periodic heat transfer coefficient, which is used to test the heat flow and heat transfer coefficient of different materials and raw materials under different heat transfer cycles, to achieve The calculation speed is fast and the calculation accuracy is high.

为解决上述问题，本发明采用如下技术方案：In order to solve the above problems, the present invention adopts the following technical solutions:

一种测定周期性换热系数的实验方法，其包括一实验装置，该装置包括可调节转速的转动滚筒、可调节喷射角度和喷射高度的喷嘴、置于滚筒内部的加热装置、埋设于滚筒筒体内的热电偶、电连至热电偶及将温度信号输出的温度收集装置；An experimental method for measuring the periodic heat transfer coefficient, which includes an experimental device, which includes a rotating drum with adjustable speed, a nozzle with adjustable spray angle and spray height, a heating device placed inside the drum, and a drum embedded in the drum. Thermocouples in the body, temperature collection devices electrically connected to the thermocouples and outputting temperature signals;

具体实验方法包括以下步骤：The specific experimental method includes the following steps:

第一步：利用需要测试的材质制成转动滚筒，置于实验装置上，根据测试需要调节好滚筒的转速；根据所需模拟的冷却环境，调节好喷嘴的喷射高度以及喷射角度；利用加热装置对滚筒进行加热；The first step: use the material to be tested to make a rotating drum, place it on the experimental device, adjust the rotating speed of the drum according to the test needs; adjust the spray height and spray angle of the nozzle according to the simulated cooling environment; use the heating device heating the drum;

第二步，利用温度收集装置记录筒体内部温度数据，获得筒体淬火降温曲线n为设定的温度收集点个数，利用温度仪测得喷嘴冷却水的温度T_cW；The second step is to use the temperature collection device to record the internal temperature data of the cylinder to obtain the quenching and cooling curve of the cylinder n is the number of set temperature collection points, and the temperature _TcW of the nozzle cooling water is measured by a thermometer;

第三步，赋筒体表面热流初值δ为常数，i＝1,…,n；计算内部温度场 The third step is to assign the initial value of the heat flow on the surface of the cylinder δ is a constant, i=1,...,n; calculate the internal temperature field

第四步，计算灵敏度系数X_ik,利用第二步和温度场代入公式求得灵敏度系数：The fourth step is to calculate the sensitivity coefficient X _ik , using the second step and temperature field Substitute into the formula to get the sensitivity coefficient:

${X x}_{i i k k} = = \frac{\partial \partial}{\partial \partial {q q}_{k k}} (({T T}_{i i}^{c c} (({q q}_{k k})))) \approx \approx \frac{{T T}_{i i}^{c c} (({q q}_{11}^{00} ... ...,, {q q}_{k k}^{00} + + {δq δq}_{k k}^{00},, ... ... {q q}_{n no}^{00})) - - {T T}_{i i}^{c c} (({q q}_{11}^{00} ... ...,, {q q}_{k k}^{00},, ... ... {q q}_{n no}^{00}))}{{δq δq}_{k k}};;$

第五步，求解利用前三步获得的X_ik代入公式求得优化值 The fifth step, solve obtained by using the first three steps Substituting X _ik into the formula to obtain the optimal value

${q q}_{i i}^{11} = = {q q}_{i i}^{00} + + {(({X x}_{i i k k}^{T T} {X x}_{i i k k}))}^{- - 11} {X x}_{i i k k}^{T T} (({T T}_{i i}^{m m} - - {T T}_{i i}^{c c} (({q q}_{i i}^{00}))));;$

第六步，判断是否满足收敛判The sixth step is to judge Does it satisfy the convergence criterion?

$| | \frac{{q q}_{i i}^{11} - - {q q}_{i i}^{00}}{{q q}_{i i}^{11}} | | < < ϵ ϵ,, i i = = 11,, ... ...,, n no;;$

如满足收敛，则代入公式获得传热系数h_i，结束；If the convergence is satisfied, then substitute into the formula to obtain the heat transfer coefficient h _i , and end;

${h h}_{i i} = = \frac{{q q}_{i i}^{11}}{{T T}_{i i}^{m m} - - {T T}_{c c W W}}$

如不满足收敛，则令If convergence is not satisfied, then let

${q q}_{i i}^{00} = = {q q}_{i i}^{11},, i i = = 11,, ... ...,, n no;;$

返回至第二步，直至满足收敛计算出h为止。Return to the second step until the convergence is satisfied and h is calculated.

进一步的，所述转动滚筒的材质可以根据测试需要相应选择。Further, the material of the rotating drum can be selected according to the test requirements.

进一步的，所述第三步中，利用筒体各测温点建立传热数学模型的方法如下：Further, in the third step, the method of establishing a heat transfer mathematical model using each temperature measuring point of the cylinder is as follows:

$ρ ρ c c \frac{\partial \partial T T}{\partial \partial t t} = = \frac{11}{r r} \frac{\partial \partial}{\partial \partial r r} ((r r λ λ \frac{\partial \partial T T}{\partial \partial t t})) + + \frac{11}{r r} \frac{\partial \partial}{\partial \partial θ θ} ((\frac{λ λ}{r r} \frac{\partial \partial T T}{\partial \partial θ θ})) ((r r &Element; &Element; (({s the s}_{11},, {s the s}_{22})),, θ θ &Element; &Element; [[00,, 22 π π)),, t t > > 00))$

初始条件：T(r,0)＝T₀(r∈[s₁,s₂],t＝0)Initial condition: T(r,0)=T ₀ (r∈[s ₁ ,s ₂ ],t=0)

边界条件T|_r＝s＝T_f(r＝s₁,t＞0) $- λ \frac{\partial T}{\partial r} |_{r = s_{2}} = q (t) (r = s_{2}, t > 0)$ Boundary condition T| _r=s ＝T _f (r=s ₁ ,t>0) $- λ \frac{\partial T}{\partial r} |_{r = {the s}_{2}} = q (t) (r = {the s}_{2}, t > 0)$

式中：λ为筒体导热系数/w·(m·℃)^-1；ρ为筒体密度/Kg·m^-3；C为筒体的定压比热容/J·(kg·℃)^-1；T为温度/℃；t为时刻；r为径向坐标，θ为圆周方向坐标。In the formula: λ is the thermal conductivity of the cylinder/w·(m·℃) ^-1 ; ρ is the density of the cylinder/Kg·m ^-3 ; C is the specific heat capacity of the cylinder at constant pressure/J·(kg·℃) ^-1 ; T is the temperature/℃; t is the moment; r is the radial coordinate, θ is the circumferential direction coordinate.

根据热平衡原理，在非稳态条件下，以导热方式进入筒体任意一点p的热流量的代数和等于其热量变化量，建立传热离散模型的方法如下：According to the principle of heat balance, under unsteady conditions, the algebraic sum of the heat flow entering any point p of the cylinder in the form of heat conduction is equal to the amount of heat change. The method of establishing the heat transfer discrete model is as follows:

$\{\begin{matrix} \frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} {T T}_{S S}^{k k + + 11} + + \frac{λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} {T T}_{W W}^{k k + + 11} - - ((\frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} + + \frac{22 λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} + + ρ ρ c c)) {T T}_{P P}^{k k + + 11} = = - - {ρcT ρ cT}_{P P}^{k k} - - \frac{q q (({r r}_{P P} + + Δ Δ r r / / 22))}{{r r}_{P P} Δ Δ r r} \\ ((m m = = 11)) \\ \frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} {R R}_{S S}^{k k + + 11} + + \frac{λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} {T T}_{W W}^{k k + + 11} - - ((\frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} + + \frac{22 λ λ}{{r r}_{P P}^{22} {Δr Δr}^{22}} + + ρ ρ c c)) {T T}_{P P}^{k k + + 11} + + \frac{λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} {T T}_{E E.}^{k k + + 11} + + \frac{λ λ (({r r}_{P P} + + Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} {T T}_{N N}^{k k + + 11} = = - - {ρcT ρ cT}_{P P}^{k k} \\ ((m m = = 22,, 33,, ... ...,, N N - - 11)) \\ \frac{λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} {T T}_{W W}^{k k + + 11} - - ((\frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22} / / 22} + + \frac{22 λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} + + \frac{λ λ (({r r}_{P P} + + Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} + + ρ ρ c c)) {T T}_{P P}^{k k + + 11} + + \frac{λ λ}{{r r}_{P P}^{22} {Δθ Δθ}^{22}} {T T}_{E E.}^{k k + + 11} + + \frac{λ λ (({r r}_{P P} + + Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22}} {T T}_{N N}^{k k + + 11} = = - - {ρcT ρ cT}_{P P}^{k k} - - \frac{λ λ (({r r}_{P P} - - Δ Δ r r / / 22))}{{r r}_{P P} {Δr Δr}^{22} / / 22} {T T}_{f f} \\ ((m m = = N N)) \end{matrix}$

m为任意点p所在网格的层数；为k时刻p点的温度；p点的四个方向的温度值分别T_W,T_E,T_S,T_N；r_P为p点的半径；把相应参数代入上述方程组求解从而易知热电偶所在网格处的温度 m is the number of layers of the grid where any point p is located; is the temperature at point p at time k; the temperature values in the four directions of point p are T _W , TE , T _S , T _N ; r _P is the radius of point _p ; substitute the corresponding parameters into the above equations to solve Thus it is easy to know the temperature at the grid where the thermocouple is located

进一步的，设定所述ε<0.001。Further, set the ε<0.001.

进一步的，所述温度收集点个数n＝24，其分布依据为时间步长Δτ＝1s，空间步长Δθ＝π/12，Δr＝1mm。Further, the number of temperature collection points is n=24, and the distribution is based on the time step Δτ=1s, the space step Δθ=π/12, and Δr=1mm.

本发明的有益效果：Beneficial effects of the present invention:

(1)本发明装置中由于采用转动滚筒的形式，很好地克服了热应力的形变问题，现有技术中钢板冷却的形变较大，数次实验后形变严重，无法多次重复实验，而滚筒很好地解决了这一问题，能够多次重复实验，且采用滚筒的形式使得滚筒内部更接近绝热状态，与实际二次冷却中钢坯的中间绝热状态相一致。(1) Owing to adopting the form of rotating drum in the device of the present invention, the deformation problem of thermal stress has been overcome well, the deformation of steel plate cooling in the prior art is bigger, deformation is serious after several experiments, can't repeat experiment repeatedly, and The drum solves this problem very well, and the experiment can be repeated many times, and the form of the drum makes the inside of the drum closer to the adiabatic state, which is consistent with the intermediate adiabatic state of the billet in the actual secondary cooling.

(2)本发明的滚筒可以由所需测量的材料制成，适用于多种不同材质坯料传热系数的测定。(2) The drum of the present invention can be made of the materials to be measured, and is suitable for the determination of the heat transfer coefficients of blanks of various materials.

(3)本发明滚筒转速可调，喷嘴的喷射高度和喷射角度均可调，因此可以模拟多种冷却形式，实现周期性冷却测试，从而可以测试出不同冷却周期的冷却特性。(3) The rotation speed of the drum of the present invention is adjustable, and the spray height and spray angle of the nozzles are both adjustable, so various cooling forms can be simulated to realize periodic cooling tests, so that the cooling characteristics of different cooling cycles can be tested.

(4)本发明实验方法过程中包括反问题算法的验证过程，验证了反问题算法的正确性和可行性，使得实验所得数据更加可靠。(4) The verification process of the inverse problem algorithm is included in the experimental method of the present invention, which verifies the correctness and feasibility of the inverse problem algorithm, making the experimental data more reliable.

(5)本发明实验方法考虑到了输入热流时间分布、所有时刻所有通道误差对实验精度的影响，将实验误差均值级别控制在10^-14数量级，精度极高。(5) The experimental method of the present invention takes into account the influence of the input heat flow time distribution and all channel errors at all times on the experimental accuracy, and controls the average level of the experimental error to an order of magnitude of 10 ^-14 , with extremely high accuracy.

附图说明Description of drawings

图1为本发明数学模型的建立示意图；Fig. 1 is the establishment schematic diagram of mathematical model of the present invention;

图2为本发明数学模型网格划分示意图；Fig. 2 is a schematic diagram of grid division of the mathematical model of the present invention;

图3为本发明反问题计算方法流程图；Fig. 3 is the flow chart of the calculation method of the inverse problem of the present invention;

图4为本发明反问题计算方法验证流程图；Fig. 4 is the verification flowchart of the inverse problem calculation method of the present invention;

图5为本发明输入热流时间分布图；Fig. 5 is the input heat flow time distribution diagram of the present invention;

图6为本发明误差验证实验图；Fig. 6 is the experimental figure of error verification of the present invention;

图7为本发明实验装置的示意图；Fig. 7 is the schematic diagram of experimental device of the present invention;

具体实施方式detailed description

本发明提供了一种测定周期性换热系数的实验方法，其所使用的实验装置如图7所示(仅示意出喷嘴和滚筒)，包括可调节转速的转动滚筒、可调节喷射角度和喷射高度的喷嘴、置于滚筒内部的加热装置、埋设于滚筒筒体内的热电偶、电连至热电偶及将温度信号输出的温度收集装置。The present invention provides an experimental method for measuring the periodic heat transfer coefficient. The experimental device used in it is as shown in Figure 7 (only the nozzle and the drum are shown schematically), including a rotating drum with adjustable speed, adjustable spray angle and spray High nozzle, a heating device placed inside the drum, a thermocouple embedded in the drum body, a temperature collection device electrically connected to the thermocouple and outputting a temperature signal.

具体的测试方法如下：The specific test method is as follows:

首先，利用需要测试的材质制成转动滚筒，置于实验装置上，根据测试需要调节好滚筒的转速；First, use the material to be tested to make a rotating drum, place it on the experimental device, and adjust the rotating speed of the drum according to the test needs;

其次，根据所需模拟的冷却环境，调节好喷嘴的喷射高度以及喷射角度；Secondly, adjust the spray height and spray angle of the nozzle according to the simulated cooling environment;

最后，利用加热装置对滚筒进行加热，测得滚筒上24个测温点的温度值。Finally, the drum is heated by a heating device, and the temperature values of 24 temperature measuring points on the drum are measured.

具体的计算步骤如下：The specific calculation steps are as follows:

第一步，利用温度收集装置记录筒体内部温度数据，获得筒体淬火降温曲线利用温度仪测出喷嘴中冷却水的温度T_cW；The first step is to use the temperature collection device to record the internal temperature data of the cylinder to obtain the quenching and cooling curve of the cylinder Use a thermometer to measure the temperature T _cW of the cooling water in the nozzle;

第二步，赋筒体表面热流初值计算内部温度场 The second step is to assign the initial value of the heat flow on the surface of the cylinder Calculate the internal temperature field

根据24个测温点数据建立传热数学模型，如图1所示，Based on the data of 24 temperature measurement points, a heat transfer mathematical model is established, as shown in Figure 1.

1、 $ρ c \frac{\partial T}{\partial t} = \frac{1}{r} \frac{\partial}{\partial r} (r λ \frac{\partial T}{\partial t}) + \frac{1}{r} \frac{\partial}{\partial θ} (\frac{λ}{r} \frac{\partial T}{\partial θ}) (r &Element; (s_{1}, s_{2}), θ &Element; [0, 2 π), t > 0)$ 1, $ρ c \frac{\partial T}{\partial t} = \frac{1}{r} \frac{\partial}{\partial r} (r λ \frac{\partial T}{\partial t}) + \frac{1}{r} \frac{\partial}{\partial θ} (\frac{λ}{r} \frac{\partial T}{\partial θ}) (r &Element; ({the s}_{1}, {the s}_{2}), θ &Element; [0, 2 π), t > 0)$

2、初始条件：T(r,0)＝T₀(r∈[s₁,s₂],t＝0)2. Initial conditions: T(r,0)=T ₀ (r∈[s ₁ ,s ₂ ],t=0)

3、边界条件T|_r＝s＝T_f(r＝s₁,t＞0)3. Boundary condition T| _r=s ＝T _f (r=s ₁ ,t>0)

$- - λ λ \frac{\partial \partial T T}{\partial \partial r r} {| |}_{r r = = {s the s}_{22}} = = q q ((t t)) ((r r = = {s the s}_{22},, t t > > 00))$

θ方向共有24个位置测试点，取用时间步长Δτ＝1s，空间步长Δθ＝π/12，Δr＝1mm，初始温度T₀＝1200℃，物性参数，本实施例选取304不锈钢，如下：ρ＝7800kg·m^-1；λ＝0.0147T+15w·(m·k)^-1；c＝0.15T+505J·(kg·k)^-1；There are 24 position test points in the θ direction, taking the time step Δτ=1s, the space step Δθ=π/12, Δr=1mm, the initial temperature T ₀ =1200°C, and the physical parameters. In this embodiment, 304 stainless steel is selected, as follows : ρ=7800kg·m ^-1 ; λ=0.0147T+15w(m·k) ^-1 ; c=0.15T+505J(kg·k) ^-1 ;

根据热平衡原理，在非稳态条件下，以导热方式进入筒体任意一点p的热流量的代数和等于其热量变化量，建立传热离散模型，如图2所示：According to the principle of heat balance, under unsteady conditions, the algebraic sum of the heat flow entering any point p of the cylinder in the form of heat conduction is equal to the amount of heat change, and a discrete model of heat transfer is established, as shown in Figure 2:

内部节点P与其在r方向相邻节点N，S，与其在θ方向相邻节点为W，E，各温度可用相应的节点温度T_N，T_S，T_W，T_E表示。The internal node P and its adjacent nodes N, S in the r direction, and its adjacent nodes in the θ direction are W, E, and each temperature can be represented by the corresponding node temperature T _N , T _S , T _W , T _E.

把相应参数代入上述方程组求解从而易知热电偶所在网格处的温度 Substitute the corresponding parameters into the above equations to solve Thus it is easy to know the temperature at the grid where the thermocouple is located

第三步，计算灵敏度系数X,利用第二步和温度场代入公式求得灵敏度系数：The third step is to calculate the sensitivity coefficient X, using the second step and temperature field Substitute into the formula to get the sensitivity coefficient:

第四步，求解利用前三步获得的X代入公式求得优化值 The fourth step, solve obtained by using the first three steps Substituting X into the formula to obtain the optimal value

第五步，判断是否满足收敛判据The fifth step is to judge Whether the convergence criterion is satisfied

$| | \frac{{q q}_{i i}^{11} - - {q q}_{i i}^{00}}{{q q}_{i i}^{11}} | | < < ϵ ϵ,, i i = = 11,, ... ...,, 24 twenty four;;$

ε＝0.001，如满足收敛，则代入公式获得传热系数h，结束；ε=0.001, if the convergence is satisfied, then substitute into the formula to obtain the heat transfer coefficient h, and end;

如不满足收敛，则令If convergence is not satisfied, then let

${q q}_{i i}^{00} = = {q q}_{i i}^{11},, i i = = 11,, ... ...,, 24 twenty four;;$

验证过程如图4所示：The verification process is shown in Figure 4:

实验过程是通过实验获取缸体表层离散点的温度信息，通过反问题计算得出表面热流或温度的曲线及分布，在实验之前我们需要对反问题模型进行验证，模拟是通过假定热流边界计算出温度场，提取表面温度离散点信息来作为实验温度离散点数据，通过反问题计算出表面热流密度值，比较计算热流密度与假定热流密度来验证反问题及时空转换模型和程序的可行性。The experimental process is to obtain the temperature information of the discrete points on the surface of the cylinder through the experiment, and calculate the surface heat flow or temperature curve and distribution through the inverse problem. Before the experiment, we need to verify the inverse problem model. The simulation is calculated by assuming the heat flow boundary. For the temperature field, the surface temperature discrete point information is extracted as the experimental temperature discrete point data, the surface heat flux value is calculated through the inverse problem, and the calculated heat flux density is compared with the assumed heat flux density to verify the feasibility of the inverse problem and space-time conversion model and program.

输入热流时间分布如图5，把温度值代入反问题程序计算出表面热流反算值，图6为所有时刻所有通道误差。可以发现误差微小，误差均值级别在约为10^-14数量级，精度极高。The time distribution of input heat flow is shown in Figure 5, and the temperature value is substituted into the inverse problem program to calculate the inverse value of surface heat flow. Figure 6 shows the errors of all channels at all times. It can be found that the error is small, the average level of the error is on the order of about 10 ^-14 , and the precision is extremely high.

最后应说明的是：显然，上述实施例仅仅是为清楚地说明本发明所作的举例，而并非对实施方式的限定。对于所属领域的普通技术人员来说，在上述说明的基础上还可以做出其它不同形式的变化或变动。这里无需也无法对所有的实施方式予以穷举。而由此所引申出的显而易见的变化或变动仍处于本发明的保护范围之中。Finally, it should be noted that: obviously, the above-mentioned embodiments are only examples for clearly illustrating the present invention, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. measuring an experimental technique for cyclical heat transmission coefficient, the method uses an experimental provision, and this device includes scalable The rotating cylinder, scalable spray angle and the nozzle of jetting height, be placed in the heater of drums inside, be embedded in rolling of rotating speed Thermocouple in cylinder cylinder, temperature collection device are electrically connected to thermocouple, and are exported by the temperature signal of thermocouple；

Specific experiment method comprises the following steps:

The first step: need to regulate the rotating speed of rotation cylinder according to test；According to the cooler environment of required simulation, regulate nozzle Jetting height and spray angle；Heater is utilized to heat rotating cylinder；

Second step, utilizes temperature collection device record inner barrel temperature data, it is thus achieved that cylinder quenching temperature lowering curveN is the temperature collection point number set, and utilizes thermometer to record temperature T of nozzle cooling water_cw；

3rd step, composes drum surface hot-fluid initial valueδ is constant, i=1 ..., n；Calculate internal temperature field

The each point for measuring temperature of cylinder is utilized to set up the method for mathematical Model of Heat Transfer as follows:

ρ c \frac{\partial T}{\partial t} = \frac{1}{r} \frac{\partial}{\partial r} (r λ \frac{\partial T}{\partial t}) + \frac{1}{r} \frac{\partial}{\partial θ} (\frac{λ}{r} \frac{\partial T}{\partial θ}) (r &Element; (s_{1}, s_{2}), θ &Element; [0, 2 π), t > 0)

Initial condition: T (r, 0)=T₀(r∈[s₁,s₂], t=0)

Boundary condition

\begin{matrix} T |_{r = s_{1}} = T_{f} (r = s_{1}, t > 0) & - λ \frac{\partial T}{\partial r} |_{r = s_{2}} = q (t), (r = s_{2}, t > 0) \end{matrix}

In formula: λ is cylinder heat conductivity, unit is w (m DEG C)^-1；ρ is cylinder density, and unit is Kg m^-3；C is cylinder Specific heat at constant pressure, unit is J (kg DEG C)^-1；T is temperature, and unit is DEG C；T is the moment, and unit is s；R is radial coordinate, single Position is mm；θ is circumferencial direction coordinate, and unit is radian；

According to heat balance principle, under unsteady state condition, enter the algebraical sum of the heat flow of cylinder any point p with heat-conducting mode Equal to its thermal change amount, the method setting up heat transfer discrete model is as follows:

\{\begin{matrix} \frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2}} T_{S}^{k + 1} + \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{W}^{k + 1} - (\frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2}} + \frac{2 λ}{r_{P}^{2} {Δθ}^{2}} + ρ c) T_{P}^{k + 1} + \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{E}^{k + 1} = - {ρcT}_{P}^{k} - \frac{q (r_{P} + Δ r / 2)}{r_{P} Δ r} \\ (m = 1) \\ \frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2}} T_{S}^{k + 1} + \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{W}^{k + 1} - (\frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2}} + \frac{2 λ}{r_{P}^{2} {Δθ}^{2}} + \frac{λ (r_{P} + Δ r / 2)}{r_{P} {Δr}^{2}} + ρ c) T_{P}^{k + 1} + \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{E}^{k + 1} + \frac{λ (r_{P} + Δ r / 2)}{r_{P} {Δr}^{2}} T_{N}^{k + 1} = - {ρcT}_{P}^{k} \\ (m = 2, 3, ..., N - 1) \\ \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{W}^{k + 1} + (\frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2} / 2} + \frac{2 λ}{r_{P}^{2} {Δθ}^{2}} + \frac{λ (r_{P} + Δ r / 2)}{r_{P} {Δr}^{2}} + ρ c) T_{P}^{k + 1} + \frac{λ}{r_{P}^{2} {Δθ}^{2}} T_{E}^{k + 1} + \frac{λ (r_{P} + Δ r / 2)}{r_{P} {Δr}^{2}} T_{N}^{k + 1} = - {ρcT}_{P}^{k} - \frac{λ (r_{P} - Δ r / 2)}{r_{P} {Δr}^{2} / 2} T_{f} \\ (m = N) \end{matrix}

M is the number of plies of cylinder any point p place grid；Temperature for k moment p point；The temperature value minute of the four direction of p point Wei T_W,T_E,T_S,T_N；r_PRadius for p point；Relevant parameter is substituted into above-mentioned solving equationsFrom And draw the temperature at the grid of thermocouple place

4th step, meter sensitivity coefficient X_ik, utilize the 3rd stepAnd temperature field Substitute into following formula and try to achieve sensitivity coefficient:

X_{i k} = \frac{\partial}{\partial q_{k}} (T_{i}^{c} (q_{k})) \approx \frac{T_{i}^{c} (q_{1}^{0} ..., q_{k}^{0} + {δq}_{k}^{0}, ... q_{n}^{0}) - T_{i}^{c} (q_{1}^{0} ..., q_{k}^{0}, ... q_{n}^{0})}{{δq}_{k}}

5th step, solvesFirst three step is utilized to obtainX_ikSubstitute into following formula and try to achieve optimal value

q_{i}^{1} = q_{i}^{0} + {({X_{i k}}^{T} X_{i k})}^{- 1} {X_{i k}}^{T} (T_{i}^{m} - T_{i}^{c} (q_{i}^{0})), (i = 1, ..., n)

6th step, it is judged thatWhether meet convergence criterion

| \frac{q_{i}^{1} - q_{i}^{0}}{q_{i}^{1}} | < ϵ, i = 1, ..., n;

Such as satisfied convergence, then substitute into following formula and obtain heat transfer coefficient h_i, terminate；

h_{i} = \frac{q_{i}^{1}}{T_{i}^{m} - T_{c W}}, i = 1, ..., n

As being unsatisfactory for convergence, then make

q_{i}^{0} = q_{i}^{1}, i = 1, ..., n;

Being back to second step, continue to solve, until meeting convergence, calculating h_iTill.

A kind of experimental technique measuring cyclical heat transmission coefficient the most as claimed in claim 1, the material of described rotation cylinder can To need corresponding selection according to test.

A kind of experimental technique measuring cyclical heat transmission coefficient the most as claimed in claim 1, ε < 0.001 in described 6th step.

A kind of experimental technique measuring cyclical heat transmission coefficient the most as claimed in claim 1, described temperature collection point number n= 24, temperature collection point distribution foundation is time step Δ τ=1s, spatial mesh size Δ θ=π/12, Δ r=1mm.