scholarly journals Improving surface heat flux estimation for a large lake through model optimization and two-point calibration: The case of Lake Geneva

2018 ◽  
Vol 16 (9) ◽  
pp. 576-593 ◽  
Author(s):  
Abolfazl Irani Rahaghi ◽  
Ulrich Lemmin ◽  
Andrea Cimatoribus ◽  
Damien Bouffard ◽  
Michael Riffler ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Model Optimization ◽  
Large Lake ◽  
Lake Geneva ◽  
Heat Flux Estimation ◽  
Flux Estimation

Surface heat flux estimation with wind-profiler/RASS and radiosonde observations

2000 ◽  
Vol 23 (4) ◽  
pp. 339-348 ◽  
Author(s):  
Jennifer M Jacobs ◽  
Richard L Coulter ◽  
Wilfried Brutsaert
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Wind Profiler ◽  
Heat Flux Estimation ◽  
Flux Estimation

scholarly journals Surface heat flux estimation with embedded fiber Bragg gratings measurements: Numerical study

2017 ◽  
Vol 12 ◽  
pp. 1077-1081 ◽  
Author(s):  
J. Gaspar ◽  
Y. Corre ◽  
J-L. Gardarein ◽  
M. Firdaouss ◽  
D. Guilhem ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Numerical Study ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Surface Heat ◽  
Heat Flux Estimation ◽  
Flux Estimation

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.

Application of Artificial Neural Network As a Near-Real Time Technique for Solving Non-Linear Inverse Heat Conduction Problems in a One-Dimensional Medium With Moving Boundary

2020 ◽  
Author(s):  
Hamidreza Najafi ◽  
Obinna Uyanna ◽  
Jian Zhang
Keyword(s):  
Heat Flux ◽  
Real Time ◽  
Surface Heat Flux ◽  
Moving Boundary ◽  
Temperature Data ◽  
Surface Heat ◽  
Inverse Heat Conduction ◽  
Heat Flux Estimation ◽  
Flux Estimation ◽  
Inverse Heat Conduction Problems

Abstract Developing accurate and stable solutions for inverse heat conduction problems (IHCPs) is crucial in many industrial applications where direct measurement of surface conditions, such as heat flux or temperature, is not possible in practice and temperature measurement from interior points can be obtained alternatively. IHCPs are mathematically ill-posed and therefore developing stable solutions for them is challenging. Application of intelligent algorithms for solving IHCPs has been successfully explored for several cases. In the present paper, the problem of near real-time surface heat flux estimation in a one-dimensional domain with temperature dependent material properties and moving boundary is considered. An artificial neural network (ANN) is developed to use the temperature measurement data from interior points for limited number of time steps as the inputs and calculate the surface heat flux and recession rate at the current time step as the output of the network. For this purpose, a multi-layer perceptron (MLP) network is selected, trained and tested using heat flux-temperature data that were evaluated via COMSOL Multiphysics for a 1D medium that is exposed to standard heat flux profiles on its surface (including triangular, parabolic and step function). A randomly generated heat flux profile is also applied to the surface of the medium and temperature distribution is calculated via COMSOL Multiphysics. The temperature data are then used as the inputs to the network and surface heat flux is evaluated under this condition to assess the capability of the developed ANN in surface heat flux estimation. The performance of the network when using different number of inputs (previous and future time steps from which temperature data are needed for surface heat flux estimation) as well as different network topology are explored in the presence of random measurement error. The results show that the developed approach allows accurate near real-time surface heat flux estimation in a 1-D medium with temperature dependent material properties and moving boundary. The solution of this problem can be further extended to be used in sensors for ablative thermal protection system in space vehicles.

scholarly journals The Fundamental and Application of Surface Heat Flux Estimation by Inverse Method in Cryogen Spray Cooling

2020 ◽  
Author(s):  
Bin Chen ◽  
Jia-Meng Tian ◽  
Zhi-Fu Zhou
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Global Warming ◽  
Global Warming Potential ◽  
Surface Heat Flux ◽  
Spray Cooling ◽  
Surface Heat ◽  
Flux Estimation ◽  
Filter Solution ◽  
2D Filter

Surface heat flux is an important parameter in various industrial applications, which is often estimated based on measured temperature by solving inverse heat conduction problem (IHCP). In this chapter, the available IHCP methods including sequential function specification (SFS), transfer function (TF) and Duhamel’s theorem were compared, taking the example of surface heat flux estimation during spray cooling. The Duhamel’s theorem was improved to solve 1D multi-layer ICHP. Considering the significant nonuniformity of heat transfer, the 2D filter solution method was proposed to estimate surface heat flux for 2D multi-layer mediums. The maximum heat flux calculated by the 1D method was underestimated by 60% than that calculated by 2D filter solution, indicating that the lateral heat transfer cannot be ignored. The cooling performances based on 2D filter solution demonstrated that substituting the environment friendly R1234yf for R134a can remarkably reduce global warming potential to <1, but its cooling capacity is insufficient. The effective heat flux of R1234yf can be enhanced by 18.8% by reducing the nozzle diameter and decreasing the back pressure, providing the theoretical basis for the clinical potential substitution of R1234yf with low global warming potential (GWP) for commercial R134a with high GWP in laser dermatology.

Analysis of significant measures for thermal conductivity

2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Flux Density ◽  
Measurement Method ◽  
Conductivity Measurement ◽  
Surface Heat ◽  
Measuring Instrument ◽  
New Class ◽  
Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

Sign in / Sign up

Export Citation Format

Share Document