Analysis of classical Fourier, SPL and DPL heat transfer model in biological tissues in presence of metabolic and external heat source

2015 ◽  
Vol 52 (6) ◽  
pp. 1089-1107 ◽  
Author(s):  
Dinesh Kumar ◽  
Surjan Singh ◽  
K. N. Rai
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Biological Tissues ◽  
Heat Transfer Model ◽  
External Heat ◽  
Transfer Model ◽  
External Heat Source

scholarly journals Numerical Analysis and Experimental Verification of Optimum Heat Input in Additive Manufacturing of Aero Ultrathin Blade

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Shijie Dai ◽  
Miao Gong ◽  
Liwen Wang ◽  
Tao Wang
Keyword(s):  
Heat Transfer ◽  
Additive Manufacturing ◽  
Numerical Analysis ◽  
Heat Source ◽  
Heat Input ◽  
Source Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Heat Source Model ◽  
Blade Repair

Heat input is a crucial factor affecting the quality in blade additive manufacturing repairing. First, a moving heat source model was established, and through numerical analysis and experimental comparison, the optimal geometric parameters of the heat source model for ultrathin blade repair were obtained. Second, a heat transfer model is established based on the optimal heat source model. By analyzing the thermophysical properties of different alloys, the heat input range of the blade was calculated. By heat transfer calculation under different heat inputs, the heat transfer model of blade repair was optimized. Then, a mathematical model of additive height is established. The optimized heat transfer model is used to solve the temperature distribution of the additive section with time under different wire feeding speeds through numerical analysis, which further reduced the heat input range. Third, the experiments are carried out based on the results of numerical analysis. The evolution law of the microstructure and heat input rate of the additive manufacturing zone was revealed, and the optimal heat input parameters were obtained. Under the optimal parameters, the segregation zone disappeared; hence, the test data were close to the base metal, and the additive manufacturing zone achieved better quality. The results and methods are of great guiding significance for the optimization design in additive manufacturing repair of the aero blades. The study also contributes to carrying out a series of research on heat transfer of ultrathin nickel-based alloy welding.

Mathematical and numerical analysis of thermal distribution in cancerous tissues under the local heat therapy

2017 ◽  
Vol 10 (07) ◽  
pp. 1750099 ◽  
Author(s):  
M. A. Khanday ◽  
Khalid Nazir
Keyword(s):  
Heat Source ◽  
Mathematical Formulation ◽  
Initial Boundary ◽  
Thermal Fluctuations ◽  
Local Heat ◽  
Atmospheric Temperature ◽  
Biological Tissues ◽  
External Heat ◽  
External Heat Source

The main purpose of this study is to investigate the thermal behavior of living tissues in the presence of spatial external heat source. An effort has been made to formulate the mathematical model to study the temperature distribution in in vivo tissues of the human body. The mathematical formulation is governed by bio-heat equation together with appropriate initial, boundary and interface conditions. The solution of the model was carried out using variational finite element method and computational simulations. The model describes the exchange of heat between the internal biological tissues and other surrounding media. The effect of external heat source under different conditions of atmospheric temperature and as a local hyperthermic method provides an important information to the temperature regulation in biological tissues under normal and malignant conditions. Thermal fluctuations at the targeted regions were obtained with respect to various time-dependent heating sources and scattering coefficients. The results obtained may be helpful for clinical purposes especially in the treatment of cancerous tumors through radiotherapy and other local hyperthermic approaches.

Design and Optimization of a Thermal Knudsen Force Actuated Microbeam System

2013 ◽  
Author(s):  
Mizuki Wada ◽  
Lin Sun ◽  
Alina Alexeenko
Keyword(s):  
Heat Source ◽  
Thermal Gradient ◽  
Gas Flow ◽  
Rarefied Gas ◽  
External Heat ◽  
Interface Condition ◽  
Gap Effect ◽  
Thermoelectric Device ◽  
Transfer Model ◽  
External Heat Source

Thermal Knudsen forces arise in microsystem in presence of a thermal gradient and a rarefied gas environment due to the non-equilibrium energy exchange between gas molecules and solid surfaces. Knudsen force can be used as an alternative actuation mechanism for microactuators. The purpose of this work is to design and optimize a Knudsen force actuated microbeam using modeling and simulation. The microbeam is heated by an external heat source that causes a thermal gradient between the beam and substrate. The characteristic domain size is small enough so that the rarefied gap effect is present. The study focuses on three major components that influence the Knudsen force significantly, including geometry of microbeam, external heat input to the system, and the radiometric effects generated by Peltier thermoelectric device. A Boltzmann-ESBGK model is implemented to simulate the rarefied gas flow and a continuous Fourier heat transfer model is used to solve the beam temperature field generated by the external heat source, and the fluid and solid regions are coupled using an effective heat convection interface condition.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

An Engine Heat Transfer Model for Comprehensive Thermal Simulations

2006 ◽  
Author(s):  
Filip Kitanoski ◽  
Wolfgang Puntigam ◽  
Martin Kozek ◽  
Josef Hager
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Thermal Simulations
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