scholarly journals Identification of the Thermal Constants of the DPL Heat Transfer Model of a Single Layer Porous Material

2021 ◽  
Vol 25 (2) ◽  
pp. 41-46
Author(s):  
Maria Strąkowska ◽  
Gilbert De Mey ◽  
Bogusław Więcek
Keyword(s):  
Heat Transfer ◽  
Porous Materials ◽  
Single Layer ◽  
Optimization Methods ◽  
Parameters Estimation ◽  
Transfer Model ◽  
Phase Lag ◽  
Thermal Constants ◽  
The Laplace Transform ◽  
3D Printed

This paper deals with parameters’ identification of the Dual Phase Lag (DPL) thermal model of a 3D printed porous materials. The experiments were performed for two porous materials with different filling factors. The Laplace transform was applied for the heat transfer equation and together with different optimization methods it allowed to identify the thermal time constants of the DPL model. Several optimization methods were tested with known parameters in order to confirm the correctness of the parameters’ estimation.

scholarly journals An analytical method to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation

2021 ◽  
pp. 014459872199800
Author(s):  
Xiaolong Wang ◽  
Wenke Zhang ◽  
Qingqing Li ◽  
Zhenqiang Wei ◽  
Wenjun Lei ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Internal Heat ◽  
Single Layer ◽  
Heat Radiation ◽  
Transfer Model ◽  
Cooling Systems ◽  
Average Temperature ◽  
Floor Surface ◽  
Floor Structure

Radiant floor cooling systems are increasingly used in practice. The temperature distribution on the floor surface and inside the floor structure, especially the minimum and average temperature of floor surface, determines the thermal performance of radiant floor systems. A good temperature distribution of the floor structure is very important to prevent occupant discomfort and avoid possible condensation in summer cooling. In this study, based on the heat transfer model of the single-layer homogeneous floor structure when there is no internal heat radiation in the room, this paper proposes a heat transfer model of single-layer floor radiant cooling systems when the room has internal heat radiation. Using separation variable methods, an analytical solution was developed to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation, which can be used to calculate the minimum temperature and the average temperature of typical composite floor structure. The analytical solution was validated by experiments. The values of the measured experiments are in a good agreement with the calculations. The absolute error between the calculated and the measured floor surface temperatures was within 0.45°C. The maximum relative error was within 2.31%. Prove that this model can be accepted. The proposed method can be utilized to calculate the cooling capacity of a typical multi-layer composite floor and will be developed in the future study for design of a typical radiant floor cooling system.

Numerical Heat Transfer Model of Buried Pipe and Ground Thermal Conductivity Measurement

2011 ◽  
Vol 99-100 ◽  
pp. 112-115
Author(s):  
Ming Zhi Yu ◽  
Lei Zhang ◽  
Xiao Fei Yu ◽  
Zhao Hong Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Estimation Method ◽  
Conductivity Measurement ◽  
Heat Transfer Model ◽  
Parameters Estimation ◽  
Transfer Model ◽  
Buried Pipe ◽  
Geothermal Heat ◽  
Numerical Heat Transfer

A two dimensional numerical heat transfer model of buried geothermal heat exchanger has been established by finite element method. This model is used to analyse the heat transfer between buried vertical pipes and the ground, and determine the ground thermal properties together with parameters estimation method. The ground thermal conductivity of an actual project was measured and the analysis shows that the results can be used for engineering design.

Relationship Between the Nonlocal Effect and Lagging Behavior in Bioheat Transfer

2021 ◽  
Author(s):  
Xiaoya Li ◽  
Yan Li ◽  
Pengfei Luo ◽  
Xiao Geng Tian
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Order Effect ◽  
Heat Transfer Process ◽  
Bioheat Transfer ◽  
Transfer Model ◽  
Phase Lag ◽  
Medical Systems ◽  
Conduction Model ◽  
Transfer Equations

Abstract Lots of generalized heat conduction models have been developed in recent decades, such as local thermal non-equilibrium model, phase lagging model and nonlocal heat conduction model. But no attempt was made to prove which model is better (or worse) than others, or whether there is a certain relationship between these different models. With this inspiration, we establish the nonlocal bioheat transfer equations with lagging time, and the two and three-temperature bioheat transfer equations with considering all the carries' heat conduction effect are also constructed. Comparing the two (or three)-temperature equation model with the nonlocal bioheat transfer models with lagging time, one may obtain: the lagging time tt of temperature gradient and the nonlocal characteristic length ?q in the space derivative items of heat flux have the same effect on heat transfer; when the heat transport occur among N energy carriers with considering the conduction effects of all carries, the heat transfer process are depend on the high-order effect of tqN-1, ttN-1 and ?t(2N-1) in nonlocal dual phase lag bioheat transfer model. This phenomenon is very important for biological and medical systems where numerous carriers may exist on the cellular level.

scholarly journals Investigation of Heat Diffusion at Nanoscale Based on Thermal Analysis of Real Test Structure

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2379 ◽  
Author(s):  
Tomasz Raszkowski ◽  
Mariusz Zubert
Keyword(s):  
Heat Transfer ◽  
Numerical Algorithms ◽  
Silicon Layer ◽  
Heat Transfer Model ◽  
Test Structure ◽  
Heat Diffusion ◽  
Transfer Model ◽  
Phase Lag ◽  
Bottom Part ◽  
Proposed Model

This paper presents an analysis related to thermal simulation of the test structure dedicated to heat-diffusion investigation at the nanoscale. The test structure consists of thin platinum resistors mounted on wafer made of silicon dioxide. A bottom part of the structure contains the silicon layer. Simulations were carried out based on the thermal simulator prepared by the authors. Simulation results were compared with real measurement outputs yielded for the mentioned test structure. The authors also propose the Grünwald–Letnikov fractional space-derivative Dual-Phase-Lag heat transfer model as a more accurate model than the classical Fourier–Kirchhoff (F–K) heat transfer model. The approximation schema of proposed model is also proposed. The accuracy and computational properties of both numerical algorithms are presented in detail.

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