scholarly journals An inverse method to estimate stem surface heat flux in wildland fires

2009 ◽  
Vol 18 (6) ◽  
pp. 711 ◽  
Author(s):  
Anthony S. Bova ◽  
Matthew B. Dickinson
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Inverse Method ◽  
Wildland Fire ◽  
Thermal Response ◽  
Surface Heat ◽  
Tree Bark ◽  
Inverse Heat Conduction ◽  
Heat Flux Sensors ◽  
Surface Thermocouple

Models of wildland fire-induced stem heating and tissue necrosis require accurate estimates of inward heat flux at the bark surface. Thermocouple probes or heat flux sensors placed at a stem surface do not mimic the thermal response of tree bark to flames. We show that data from thin thermocouple probes inserted just below the bark can be used, by means of a one-dimensional inverse heat conduction method, to estimate net heat flux (inward minus outward heat flow) and temperature at the bark surface. Further, we estimate outward heat flux from emitted water vapor and bark surface re-radiation. Estimates of surface heat flux and temperature made by the inverse method confirm that surface-mounted heat flux sensors and thermocouple probes overestimate surface heat flux and temperature. As a demonstration of the utility of the method, we characterized uneven stem heating, due to leeward, flame-driven vortices, in a prescribed surface fire. Advantages of using an inverse method include lower cost, ease of multipoint measurements and negligible effects on the target stem. Drawbacks of the simple inverse model described herein include inability to estimate heat flux in very moist bark and uncertainty in estimates when extensive charring occurs.

Finite Element Formulation for Two-Dimensional Inverse Heat Conduction Analysis

1992 ◽  
Vol 114 (3) ◽  
pp. 553-557 ◽  
Author(s):  
T. R. Hsu ◽  
N. S. Sun ◽  
G. G. Chen ◽  
Z. L. Gong
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Heat Conduction ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Element Formulation ◽  
Two Dimensional ◽  
Inverse Heat Conduction ◽  
Discrete Point ◽  
Element Algorithm

This paper presents a finite element algorithm for two-dimensional nonlinear inverse heat conduction analysis. The proposed method is capable of handling both unknown surface heat flux and unknown surface temperature of solids using temperature histories measured at a few discrete point. The proposed algorithms were used in the study of the thermofracture behavior of leaking pipelines with experimental verifications.

A Near Real-Time Solution Approach for Surface Heat Flux Estimation in One Dimensional Inverse Heat Conduction Problems With Moving Boundary

2019 ◽  
Author(s):  
Obinna Uyanna ◽  
Hamidreza Najafi
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Real Time ◽  
Surface Heat Flux ◽  
Moving Boundary ◽  
Surface Heat ◽  
Inverse Heat Conduction ◽  
Heat Flux Estimation ◽  
Flux Estimation ◽  
Inverse Heat Conduction Problems

Abstract Developing accurate and efficient solutions for inverse heat conduction problems allows advancements in the heat flux measurement techniques for many applications. In the present paper, a one-dimensional medium with a moving boundary is considered. It is assumed that two thermocouples are used to measure temperature at two locations within the medium while the front boundary is moving towards the back surface. Determining surface heat flux using measured temperature data is an inverse heat conduction problem. A filter based Tikhonov regularization method is used to develop a solution for this problem. Filter coefficients are calculated for various thicknesses of the medium. It is demonstrated that the filter coefficients can be interpolated to calculate the appropriate values for each thickness while it is continuously moving at a known rate. The use of filter method allows near real-time heat flux estimation. The developed solution is validated through several numerical test cases including a test case for a moving boundary in a medium modeled in COMSOL. It is shown that the proposed solution can effectively estimate the surface heat flux on the moving boundary in a near real-time fashion.

Inverse Heat Flux Problem in Quenching

2000 ◽  
Author(s):  
M. Khairul Alam ◽  
Rex J. Kuriger ◽  
Rong Zhong
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Surface Heat Flux ◽  
Measurement Errors ◽  
Heat Conduction Problem ◽  
Temperature Data ◽  
Surface Heat ◽  
Measured Temperature ◽  
Inverse Heat Conduction ◽  
Quenching Process

Abstract The quenching process is an important heat treatment method used to improve material properties. However, the heat transfer during quenching is particularly difficult to analyze and predict. To collect temperature data, quench probes have been used in controlled quenching experiments. The process of determination of the heat flux at the surface from the measured temperature data is the Inverse Heat Conduction Problem (IHCP), which is extremely sensitive to measurement errors. This paper reports on an experimental and theoretical study of quenching which is carried out to determine the surface heat flux history during a quenching process by an IHCP algorithm. The inverse heat conduction algorithm is applied to experimental data from a quenching experiment. The surface heat flux is then calculated, and the theoretical curve is compared with experimental results.

scholarly journals Analysis of One Dimensional Inverse Heat Conduction Problem : A Review

2012 ◽  
pp. 126-131
Author(s):  
Rakesh Kumar ◽  
Jayesh. P ◽  
Niranjan Sahoo
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Temperature Change ◽  
Surface Heat Flux ◽  
Working Condition ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Surface Heat ◽  
Inverse Heat Conduction ◽  
One Dimensional

A procedure to solve inverse heat conduction problem (IHCP) is to derive surface heat flux and temperature from temperature change inside a solid. The method proves to be very useful and powerful when a direct measurement of surface heat flux and temperature is difficult, owing to several working condition. The literature reviewed here discussion one dimensional inverse heat conduction problem. Procedure, criteria, methods and important results of other investigation are briefly discussed.

Effect of Part Size on Surface Heat Flux during Immersion Quenching

2012 ◽  
Vol 488-489 ◽  
pp. 353-357 ◽  
Author(s):  
K. Babu
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Transfer Rate ◽  
Temperature Data ◽  
Surface Heat ◽  
Inverse Heat Conduction ◽  
Quench Probe ◽  
Probe Diameter ◽  
Peak Heat Flux ◽  
Different Diameters

In this paper, the effect of quench probe diameter on the heat transfer rate during immersion quenching of stainless steel (SS) probes in still water has bee studied. Quench probes of different diameters with an aspect ratio of 2.5 were prepared from SS. These probes were heated to 850 °C and then quenched in water. Time-temperature data were recorded during quenching. The surface heat flux and temperature were estimated based on the inverse heat conduction (IHC) method. The results of the computation showed that the different cooling regimes during quenching in water were significantly affected by the diameter of the quench probes. The peak heat flux was higher for the probe having larger diameter followed by the next larger diameter probes.

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