A numerical study on the thermal response in multi-layer of skin tissue subjected to heating and cooling procedures

2022 ◽  
Vol 137 (1) ◽  
Author(s):  
Rajneesh Kumar Chaudhary ◽  
Vikas Chaurasiya ◽  
Mohamed M. Awad ◽  
Jitendra Singh
Keyword(s):  
Numerical Study ◽  
Thermal Response ◽  
Skin Tissue ◽  
Heating And Cooling

Numerical simulation of the tree higro-thermal response in forest fire environment

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  
Keyword(s):  
Forest Fire ◽  
Numerical Study ◽  
Thermal Response ◽  
View Factor ◽  
Tree Model ◽  
Pine Tree ◽  
Surface Temperatures ◽  
Fire Environment ◽  
Fire Front ◽  
Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

Modeling and Design of Building-Integrated Thermoelectrics

2011 ◽  
Author(s):  
Leon M. Headings ◽  
Gregory N. Washington
Keyword(s):  
Thermal Response ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Net Energy ◽  
Arbitrary Boundary ◽  
Heating And Cooling ◽  
Temperature Oscillations ◽  
Wall Structures ◽  
And Control

The goal of this research is to develop a framework for replacing conventional heating and cooling systems with distributed, continuously and electrically controlled, building-integrated thermoelectric (BITE) heat pumps. The coefficient of performance of thermoelectric heat pumps increases as the temperature difference across them decreases and as the amplitude of temperature oscillations decreases. As a result, this research examines how thermal insulation and mass elements can be integrated with thermoelectrics as part of active multi-layer structures in order to minimize net energy consumption. In order to develop BITE systems, an explicit finite volume model was developed to model the dynamic thermal response of active multi-layer wall structures subjected to arbitrary boundary conditions (interior and exterior temperatures and interior heat loads) and control algorithms. Using this numerical model, the effects of wall construction on net system performance were examined. These simulation results provide direction for the ongoing development of BITE systems.

Applicability of thermal response tests in designing standing column well system: A numerical study

Energy ◽  
2016 ◽  
Vol 109 ◽  
pp. 679-693 ◽  
Author(s):  
Jun-Seo Jeon ◽  
Seung-Rae Lee ◽  
Woo-Jin Kim
Keyword(s):  
Numerical Study ◽  
Thermal Response ◽  
System A

Axisymmetric numerical study on thermal response of composites to laser irradiation

2014 ◽  
Vol 26 (9) ◽  
pp. 91024
Author(s):  
张家雷 Zhang Jialei ◽  
王伟平 Wang Weiping ◽  
刘仓理 Liu Cangli
Keyword(s):  
Laser Irradiation ◽  
Numerical Study ◽  
Thermal Response

Optimal Multistage Expansion Planning of a Gas Turbine Cogeneration Plant

1996 ◽  
Vol 118 (4) ◽  
pp. 803-809 ◽  
Author(s):  
R. Yokoyama ◽  
K. Ito ◽  
Y. Matsumoto
Keyword(s):  
Gas Turbine ◽  
Energy Demand ◽  
Numerical Study ◽  
District Heating ◽  
Development Project ◽  
Planning Problem ◽  
Optimization Approach ◽  
Cogeneration Plant ◽  
Expansion Planning ◽  
Heating And Cooling

A multistage expansion planning problem is discussed concerning a gas turbine cogeneration plant for district heating and cooling using an optimization approach. An optimal sizing method for single-stage planning proposed by the authors is extended to this case. Equipment capacities and utility maximum demands at each expansion stage are determined so as to minimize the levelized annual total cost subject to increasing energy demands. A numerical study on a simple-cycle gas turbine cogeneration plant to be installed in a district development project clarifies the relationship between optimal expansion planning and energy demand trend, and shows the effectiveness of the proposed method.

Analysis of Hybrid Electric/Thermofluidic Control for Wet Shape Memory Alloy Actuators

2009 ◽  
Author(s):  
Leslie Flemming ◽  
Stephen Mascaro
Keyword(s):  
Control Strategies ◽  
Fluid Dynamic ◽  
Thermal Response ◽  
Electric Heating ◽  
Electrical Heating ◽  
Linear Contraction ◽  
Heating And Cooling ◽  
The Wire ◽  
Temperature Strain ◽  
Strain Model

A wet SMA actuator is characterized by an SMA wire embedded within a compliant fluid-filled tube. Heating and cooling of the SMA wire produce a linear contraction and extension of the wire. Thermal energy can be transferred to and from the wire using combinations of resistive heating and free/forced convection using hot and cold fluid. The goal of this paper is to analyze the speed and efficiency of wet SMA actuators using a variety of control strategies involving different combinations of electrical and thermofluidic inputs. A computational fluid dynamic model is used in conjunction with a temperature-strain model to simulate the thermal response of the wire and compute strains, contraction/extension times and efficiency. The simulations produce cycling rates of up to 5 Hz for electrical heating and fluidic cooling, and up to 2 Hz for fluidic heating and cooling. The results demonstrate efficiencies up to 0.5% for electric heating and up to 0.2% for fluidic heating.

The Effects of Occupancy and Solar Energy on Homes in the Pacific Northwest Constructed According to Improved Thermal Standards

2020 ◽  
Author(s):  
D. R. Heerwagen ◽  
K. Nicoliasen ◽  
A. F. Emery
Keyword(s):  
Pacific Northwest ◽  
Thermal Response ◽  
Solar Heating ◽  
Space Heating ◽  
Occupant Behavior ◽  
Single Family ◽  
Heating Season ◽  
Heating And Cooling ◽  
Energy Needs ◽  
The Pacific

Abstract The space heating energy needed during the winter heating season in Seattle Washington, USA, was monitored over a 15 year period, 1987–2002. Single family residence houses were constructed to building code standards in force at the time of construction and two more to standards calling for envelopes with improved thermal resistance. Although space conditioning energy needs are strongly affected by occupant behavior, simulations generally ignore the temporal occupant behavior in estimating the energy needed for heating and cooling. Vigorous conservation tactics, which produce a thermal response that is highly transient, can lead to substantially different energy needs. No correlation could be established from the measured space heating when aggressive conservation made use of thermostat setback at every opportunity. In this paper we investigate the effects of occupant behavior and the effect of temporal solar heating of walls in the Seattle area for improved thermal construction.

Numerical study of toroidal magnetic field on the self-gravitating protoplanetary disks

2020 ◽  
Vol 29 (09) ◽  
pp. 2050067
Author(s):  
Hanifeh Ghanbarnejad ◽  
Maryam Ghasemnezhad
Keyword(s):  
Magnetic Field ◽  
Accretion Disks ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Ohmic Heating ◽  
The Self ◽  
Toroidal Magnetic Field ◽  
Heating Process ◽  
Heating And Cooling ◽  
The Magnetic Field

In this paper, we study the self-gravitating accretion disks by considering the toroidal component of magnetic field, [Formula: see text] and wind/outflow in the flow and also investigate the effect of two parameters, [Formula: see text] and [Formula: see text] corresponding to magnetic field on the latitudinal structure of such accretion disks. The cooling of the disk is parameterized simply as, [Formula: see text] (where [Formula: see text] is the internal energy and [Formula: see text] is the cooling timescale and [Formula: see text] is a free constant) and the heating rate is decomposed into two components, magnetic field and viscosity dissipations. We have shown that when the toroidal magnetic field becomes stronger, the heating process (viscous and resistivity) and the radiative cooling rate increase. Ohmic heating is much bigger than viscous heating and cooling, so we must consider the role of the magnetic field in the energy equation. Our numerical solutions show that the thickness of the disk decreases with strong toroidal component of magnetic field. The magnetic field leads to production of the outflow in the low latitude. So, by increasing the toroidal component of the magnetic field, the regions which belong to inflow decrease and the disk is cooled.

Two-dimensional hybrid analytical approach for the investigation of thermal aspects in human tissue undergoing regional hyperthermia therapy

2020 ◽  
Vol 234 (20) ◽  
pp. 3951-3966
Author(s):  
Jaideep Dutta ◽  
Balaram Kundu
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Cancer Treatment ◽  
Thermal Response ◽  
Skin Tissue ◽  
Hyperbolic Heat Conduction ◽  
Two Dimensional ◽  
Regional Hyperthermia ◽  
Hyperthermia Therapy ◽  
The Impact

The formation of the present work is based on the development of the exact analytical solution of two-dimensional temperature response by employing the hyperbolic heat conduction bioheat model in a single-layered human skin tissue subjected to the regional hyperthermia therapy (RHT) for cancer treatment. The mathematical approach has been utilized as a hybrid form of ‘separation of variables’ and ‘finite integral transform’ method. Three kinds of surface heat fluxes (constant, sinusoidal and cosine) have been employed as an external heat source on the therapeutic surface of the square-shaped skin tissue of 100 mm × 100 mm. An innovative form of initial condition (spatially dependent) has been implemented in the present mathematical formulation as skin tissues are highly non-homogeneous and non-uniform in structure. The present research outcome indicates that cosine heat flux would be a suitable alternative for the sinusoidal heat flux. The impact of the relaxation time lag has been clearly noted in the thermal response with the waveform-like behaviour and it justifies the postulate of hyperbolic heat conduction. The two-dimensional temperature of the skin tissue has been observed in the range of 48.1 ℃–40 ℃ (in decreasing order). Estimated peak temperatures are in the proposed spectrum of hyperthermia therapy for an exposure time of 100 s, and this fact is true in an agreement with the medical protocol of the cancer treatment. The accuracy of the mathematical modelling and in-house computer codes are justified with the published numerical models and the maximum deviation of the thermal response has been noticed in order of 1.5–3%. The two-dimensional surface thermal contours have provided a glimpse of heat flow in the physical domain of skin tissue under different heating conditions and this research output may be beneficial to establish the theoretical standard of the regional hyperthermia treatment for cancer eradication.

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