Analysis of wave propagation in the presence of a continuous line heat source under heat transfer with memory dependent derivatives

2017 ◽  
Vol 23 (5) ◽  
pp. 820-834 ◽  
Author(s):  
Rakhi Tiwari ◽  
Santwana Mukhopadhyay
Keyword(s):  
Heat Transfer ◽  
Wave Propagation ◽  
Time Delay ◽  
Heat Source ◽  
Hankel Transform ◽  
Heat Transfer Process ◽  
Numerical Results ◽  
Continuous Line ◽  
Line Heat Source ◽  
With Memory

In the present work, the recently proposed new concept of “memory dependent derivative” in heat transfer process in a solid body has been employed to investigate the problem of wave propagation in a homogeneous, isotropic and unbounded solid due to a continuous line heat source. Both Laplace and Hankel transform techniques are employed for the solution of the problem. Analytical results for the distributions of different fields like temperature, displacement and stresses inside the medium have been derived. The problem is illustrated by computing the numerical values of the field variables for a particular material. We have attempted to exhibit the significance of a kernel function and a time-delay parameter that are characteristic of memory dependent derivative heat transfer in the behavior of field variables such as temperature, displacement and stresses with the help of numerical results. Detailed comparative analysis is represented through the numerical results to estimate the effects of the kernels and time-delay parameter on the behavior of all of the field variables such as temperature, displacement and stresses in the presence of a heat source in the medium.

Effects of phase lags on wave propagation in an infinite solid due to a continuous line heat source

2010 ◽  
Vol 217 (3-4) ◽  
pp. 243-256 ◽  
Author(s):  
Rajesh Prasad ◽  
Roushan Kumar ◽  
Santwana Mukhopadhyay
Keyword(s):  
Wave Propagation ◽  
Heat Source ◽  
Continuous Line ◽  
Line Heat Source ◽  
Phase Lags

Numerical Investigation on the Heat Transfer Enhancement Behavior Outside Longitudinal Finned Tubes

2018 ◽  
Author(s):  
Yujia Zhou ◽  
Hanliang Bo ◽  
Jingyu Du
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Transfer Process ◽  
Numerical Results ◽  
Transfer Model ◽  
Hydraulic Characteristics ◽  
Finned Tubes ◽  
Smooth Tubes

With the purpose of enhancement of heat transfer performance and reduction of the volume of steam generator (SG), a structure of longitudinal finned tubes was proposed to replace the smooth tubes of SG in this paper. Taking the SG smooth tubes of Daya bay Nuclear Power plant as a reference, the simplified heat transfer model of new longitudinal finned tubes was established by ANSYS CFX. Three-dimensional numerical model was developed to investigate the fluid-solid coupled thermal hydraulic characteristics of different types of the longitudinal finned tubes compared with the smooth tubes. Analysis of calculation results were sufficiently discussed for the effect of mass flow rate, fin array, solid thermal conductivity and frictional resistance. The numerical results revealed that the heat transfer coefficient increase with the increasing mass flow rate in the secondary side. The material of the tubes has significantly influence on the heat transfer process. Different flow conditions have different thermal hydraulic characteristics. The evaluated criterion to judge the enhancement of the heat transfer of the coupled process was also proposed. The numerical results can provide some useful guidance for design optimization of longitudinal finned tubes in SG.

Closed-Form Solutions of the Elastic Half Space due to a Line Heat Source

2014 ◽  
Vol 638-640 ◽  
pp. 2082-2091
Author(s):  
John C.C. Lu ◽  
Feng Tsai Lin
Keyword(s):  
Heat Source ◽  
Closed Form ◽  
Half Space ◽  
Hankel Transform ◽  
Elastic Half Space ◽  
Line Heat Source ◽  
Closed Form Solutions ◽  
Line Sink ◽  
Vertical Displacements ◽  
Thermoelastic Response

Thermoelastic response due to a line heat source is analog to poroelastic reaction caused by a fluid line sink. In this study, the strata are modeled as a thermoelastic or poroelastic half space bounded by horizontal surface in the mathematical model. Thermomechanics and poromechanics are applied on the formulation of basic governing equations, and an analogy is drawn to show the similarity. Using Hankel transform technique and approaching symbolic integral through Mathematica, the closed-form solutions of the horizontal and vertical displacements due to a fluid line sink are obtained. The displacements produced by the line heat source are described through analog quantities between thermoelasticity and poroelasticity. The solutions can be applied to dewater operations and build waste repository.

scholarly journals Effect of Heat Source Placement on Natural Convection from Cylindrical Surfaces

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4334
Author(s):  
Andrej Kapjor ◽  
Peter Durcansky ◽  
Martin Vantuch
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Theoretical Models ◽  
Heat Transfer Process ◽  
Heat Output ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Thermal Fields ◽  
Horizontal Cylinders

Placement of heat source can play a significant role in final heat output, or heat source effectivity. Because of this, there is a need to analyze thermal fields of the heat exchange system by natural convection, where the description by criterion equations is desired, as the net heat output from tubes can be quantified. Based on known theoretical models, numerical methods were adapted to calculate the heat output with natural air flow around tubes, where mathematical models were used to describe the heat transfer more precisely. After validation of heat transfer coefficients, the effect of wall and heat source placement was studied, and the Coanda effect was also observed. The heat source placement also has an effect at the boundary layer, which can change and therefore affect the overall heat transfer process. The optimal wall-to-cylinder distance for an array of horizontal cylinders near a wall was also expressed as a function of the Rayleigh number and number of cylinders in the array.

Study of the Melting Behavior in a PCM-Based Thermal Energy Storage

2015 ◽  
Author(s):  
Mohammad Bashar ◽  
Kamran Siddiqui
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Source ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Systems ◽  
Renewable Energy Sources ◽  
Heat Transfer Process ◽  
Convective Cells

Thermal energy storages are becoming important due to their significance in energy conservation as well as for the uninterrupted supply of thermal energy from renewable energy sources. The latent heat-based thermal energy storage systems utilizing phase change material (PCM) are gaining much attention due to some inherent advantages compared to sensible heat-based storage systems. However, the heat transfer process associated with the phase change in a PCM is complex and not well understood. In the present study, the melting process in a PCM-based thermal storage is experimentally studied. Two different configurations of the heat source were considered; horizontal and U-tube heat sources. The results show that the heat source shape has a significant influence on the solid to liquid phase change process (melting). The results also show that for the horizontal heat source configuration, the solid-liquid interface has a wavy profile, which is attributed to the convective cells in the melted domain of the PCM. These convective cells also influence the heat transfer coefficient, which decreased with an increase in the melted fraction. In U-tube configuration, the heat is non-uniformly transferred to the PCM domain.

Numerical Simulation of Condensation in a Rectangular Minichannel Using VOF Model

2012 ◽  
Author(s):  
Zhenyu Liu ◽  
Bengt Sunden ◽  
Jinliang Yuan
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Phase Change ◽  
Industrial Applications ◽  
Heat Transfer Process ◽  
Numerical Results ◽  
Condensation Heat Transfer ◽  
Source Terms ◽  
Two Phase ◽  
Vof Model

The understanding of two-phase flow and heat transfer with phase change in minichannels is needed for the design and optimization of heat exchangers and other industrial applications. In this study a three-dimensional numerical model has been developed to predict filmwise condensation heat transfer inside a rectangular minichannel. The Volume of Fluid (VOF) method is used to track the vapor-liquid interface. The modified High Resolution Interface Capture (HRIC) scheme is employed to keep the interface sharp. The governing equations and the VOF equation with relevant source terms for condensation are solved. The surface tension is taken into account in the modeling and it is evaluated by the Continuum Surface Force (CSF) approach. The simulation is performed using the CFD software package, ANSYS FLUENT, and an in-house developed code. This in-house code is specifically developed to calculate the source terms associated with phase change. These terms are deduced from Hertz-Knudsen equation based on the kinetic gas theory. The numerical results are validated with data obtained from the open literature. The standard k-ω model is applied to model the turbulence through both the liquid and vapor phase. The numerical results show that surface tension plays an important role in the condensation heat transfer process. Heat transfer enhancement is obtained due to the presence of the corners. The surface tension pulls the liquid towards the corners and reduces the average thermal resistance in the cross section.

scholarly journals Numerical simulation for bioconvectional flow of burger nanofluid with effects of activation energy and exponential heat source/sink over an inclined wall under the swimming microorganisms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hassan Waqas ◽  
Umar Farooq ◽  
Aqsa Ibrahim ◽  
M. Kamran Alam ◽  
Zahir Shah ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Activation Energy ◽  
Differential Equations ◽  
Heat Source ◽  
Lewis Number ◽  
Numerical Results ◽  
Solid Particles ◽  
Liquid Component ◽  
Pharmaceutical Industries ◽  
The Impact

AbstractNanofluids has broad applications such as emulsions, nuclear fuel slurries, molten plastics, extrusion of polymeric fluids, food stuffs, personal care products, shampoos, pharmaceutical industries, soaps, condensed milk, molten plastics. A nanofluid is a combination of a normal liquid component and tiny-solid particles, in which the nanomaterials are immersed in the liquid. The dispersion of solid particles into yet another host fluid will extremely increase the heat capacity of the nanoliquid, and an increase of heat efficiency can play a significant role in boosting the rate of heat transfer of the host liquid. The current article discloses the impact of Arrhenius activation energy in the bioconvective flow of Burger nanofluid by an inclined wall. The heat transfer mechanism of Burger nanofluid is analyzed through the nonlinear thermal radiation effect. The Brownian dispersion and thermophoresis diffusions effects are also scrutinized. A system of partial differential equations are converted into ordinary differential equation ODEs by using similarity transformation. The multi order ordinary differential equations are reduced to first order differential equations by applying well known shooting algorithm then numerical results of ordinary equations are computed with the help of bvp4c built-in function Matlab. Trends with significant parameters via the flow of fluid, thermal, and solutal fields of species and the area of microorganisms are controlled. The numerical results for the current analysis are seen in the tables. The temperature distribution increases by rising the temperature ratio parameter while diminishes for a higher magnitude of Prandtl number. Furthermore temperature-dependent heat source parameter increases the temperature of fluid. Concentration of nanoparticles is an decreasing function of Lewis number. The microorganisms profile decay by an augmentation in the approximation of both parameter Peclet number and bioconvection Lewis number.

Thermal Conductivity of Selected Foods at High-Pressure Processing Conditions

2018 ◽  
Vol 61 (1) ◽  
pp. 317-325 ◽  
Author(s):  
Wei Sun ◽  
Songming Zhu ◽  
Hosahalli S. Ramaswamy ◽  
Yong Yu ◽  
Jianping Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
High Pressure ◽  
Heat Source ◽  
Linear Regression Analysis ◽  
High Pressure Processing ◽  
Calibration Factor ◽  
Line Heat Source ◽  
Food Material ◽  
Processing Line

Abstract. Thermal conductivity data for foods under high-pressure processing (HPP) conditions is necessary for modeling the associated heat transfer processes, such as HP sterilization, pressure shift freezing, etc. Available data in the literature arescarcebecause of the difficulties associated with property measurements. In this study, a thermal conductivity probe based on line heat source theory was used under HPP conditions. The probe was calibrated using 1.5% agar gel in the HP range of 0.1 to 400 MPa and temperature range of 25°C to 55°C. No clear pressure, temperature, or power supply dependency trend of the calibration factor was observed. A general calibration factor (1.01) was obtained by linear regression analysis between all measured values and reference values of water at different HPP conditions. Thermal conductivities of selected food materials (tofu, wheat flour dough, and pork) were then measured under similar HPP conditions and corrected using the calibration factor. The evaluated thermal conductivity of food materials ranged from 0.40 to 0.79 W m-1 °C-1 and increased with increasing pressure and temperature. A prediction model was developed to give a good fit (R2 = 0.91) for the thermal conductivity of each food material with pressure and temperature. Keywords: Adiabatic compression heating, Food, Heat transfer, High-pressure processing, Line heat source, Thermal conductivity.

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