Application of Inverse Heat Conduction Method and Method of Lines in Spray Cooling of Heated Surface

Author(s):  
Ramin Soujoudi

This paper investigates application of Method of Lines (MOL) and Inverse Heat Conduction techniques in spray cooling process. A flat face of a heated cylinder is cooled by using a nozzle spray and using room temperature water as a cooling fluid. The numerical analysis is done using MOL to estimate exposed surface temperature, surface heat flux, and convection heat transfer coefficient [3],[4]. Since there is no exact solution to verify the approximation result, for the verification purpose and accuracy of the result, the numerical result from this study is compared to other approximation results with experimental research done by Chen-Lee and Qiao-Chandra [1]. The results illustrate that disparity between the outcome of MOL and the one generated by Chen and Lee’s raw data is very insignificant throughout the whole time domain. This discrepancy between these two estimated results proves that MOL is a very reliable approximation technique compared to other finite element methods which require a finer mesh size and significant amount of calculations[2],[5]. However, comparing the results obtained through MOL with Qiao and Chandra shows that the difference between the estimated heat transfer coefficient and estimated heat flux converges rapidly for the short times of 0 < t < 60, but as the time passes, the MOL approximation results diverge slowly until it reaches its maximum value at ninety seconds, and the variance remains almost constant for the rest of the time period.

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Bahman Abbasi ◽  
Jungho Kim

One of the main challenges of spray cooling technology is the prediction of local and average heat transfer coefficients on the heater surface. It is hypothesized that the local heat transfer coefficient can be predicted from the local normal pressure produced by the spray. In this study, hollow cone, full cone, and flat fan sprays, operated at three standoff distances, five spray pressures, and two nozzle orientations, were used to identify the relation between the impingement pressure and the heat transfer coefficient in the single-phase regime. PF-5060, PAO-2, and PSF-3 were used as test fluids, resulting in Prandtl number variation between 12 and 76. A microheater array operated at constant temperature was used to measure the local heat flux. A separate test rig was used to make impingement pressure measurements for the same geometry and spray pressure. The heat flux data were then compared with the corresponding impingement pressure data to develop a pressure-based correlation for spray cooling heat transfer. The maximum deviation between the experimental data and prediction was within ±25%.


2013 ◽  
Vol 395-396 ◽  
pp. 1135-1141
Author(s):  
Yang Yu ◽  
Xiao Chuan Luo ◽  
Yuan Wang

The surface heat transfer coefficient is obtained by the calculation of water-flowing in the second cooling zone of continuous casting; the parameters of this formula are determined by the engineering experiment methods. This paper adopts a new method-numerical calculation method to obtain these parameters. Firstly, the paper uses the method of solving inverse heat conduction problems to calculate the surface heat flux and the surface heat transfer coefficient. Secondly, by using the least square method, the parameters in the formula between the surface heat transfer coefficient and water-flowing are identified. Finally, a plant steel data is used to do some simulation experiments. The results of this simulation prove this numerical method feasibility and effectiveness.


1999 ◽  
Author(s):  
Patrick H. Oosthuizen ◽  
David Naylor

Abstract A transient method, based on an inverse heat conduction solution, for experimentally determining the distribution of local heat transfer rates on the surface of a body has been numerically evaluated. The particular interest is in situations in which the heat transfer coefficients are relatively low and in which there are relatively large changes in the heat transfer coefficient over the surface of the body being considered. In the method, a solid body of the shape being investigated, constructed from a low conductivity material, is heated to a uniform temperature and then exposed to a test flow. Using a layer of temperature sensitive crystal placed over the surface of this model or by other means, the time taken for the temperature at a relatively small number of selected points on the surface to reach a selected value is determined. The surface heat flux rate distribution is then found from these measured times using a simple inverse heat conduction method. The feasibility of this method has been evaluated by considering relatively low Reynolds number flow over a square cylinder and natural convective flow over a circular cylinder. Known local heat transfer coefficient distributions for these situation have been applied as boundary conditions in the numerical solution of the transient cooling of a the “experimental” models. These solutions are used to generate “measured” data i.e. to generate simulated experimental data. The inverse heat transfer method has then been used to predict the local heat transfer coefficient distribution over the surface and the predicted and input distributions have been compared. The effect of uncertainties in the experimental measurements on this comparison has then been evaluated using various assumed uncertainty values. The results of the study indicate that the proposed method of measuring local heat transfer coefficients is capable of giving results of good accuracy.


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