Heat Transfer in Composite Spheroids

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Rajai Alassar
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Prolate Spheroid ◽  
Published Data ◽  
Composite Sphere ◽  
Legendre Series ◽  
The Third ◽  
Type Boundary ◽  
Type Boundary Condition ◽  
The Impact

Abstract Heat transfer from a composite prolate spheroid under the third-type boundary condition is investigated using a Legendre series expansion. The model is verified against published data on cooling boiled eggs and also against the asymptotic solution of a composite sphere. The impact of Biot number on the heat transfer in spheroids with realistic dimensions and properties, such as eggs and olives, is investigated. The results are also presented for varying conductivity ratios and fractional volume of the inner part of the spheroid.

Asymptotic approach for nonlinear vibrating beams with saturation type boundary condition

2013 ◽  
Vol 227 (11) ◽  
pp. 2479-2486 ◽  
Author(s):  
Hamid M Sedighi ◽  
Kourosh H Shirazi
Keyword(s):  
Boundary Condition ◽  
Numerical Solutions ◽  
Hamiltonian Approach ◽  
Dead Band ◽  
Equivalent Function ◽  
Vibrational Response ◽  
Band Parameter ◽  
Type Boundary ◽  
Type Boundary Condition ◽  
The Impact

This article attempts to analyze the complicated vibrational behavior of the Euler–Bernoulli beam exposed to saturated nonlinear boundary condition through proposing an innovative precise equivalent function. In this direction, the beam vibrational response is attained by way of a new effective analytical method namely Hamiltonian approach. Despite all the procedures based on perturbation methods that deadzone or saturation dead-band parameter is omitted during integration, this study indicates that how using Hamiltonian approach, the impact of dead-band parameter is taken into account leading to higher accuracy of the approximated solution. Finally, the precision of the proposed equivalent function is evaluated in comparison with the numerical solutions, giving excellent results.

The Use of a Convection Boundary Condition in the Simulation of a Heat Tracer Experiment Conducted in Bedrock

2020 ◽  
Author(s):  
Kent Novakowski
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Tracer Experiment ◽  
Conductive Heat ◽  
Type Condition ◽  
Type Boundary ◽  
The Impact ◽  
The Heat Transfer Coefficient

<p>Heat transfer experiments conducted in the subsurface are usually interpreted using either analytical or numerical models, which incorporate first-type boundary conditions (specified temperature) to introduce the heat into the solution domain. An alternative approach is to use a third-type boundary condition, often refereed to as a convection bc in the heat transfer literature, which includes a heat transfer coefficient to accommodate the exchange of heat between fluid flowing outside the domain to that inside the domain under potential. To explore the impact of this boundary condition, a semi-analytical model was developed for a linear flow system in a discrete rock fracture with advective heat transfer in the fracture and conductive heat transfer in the matrix. To illustrate the influence of the heat transfer coefficient, the model is applied to the results of a heat tracer experiment conducted in a discrete fracture connecting two boreholes in a crystalline rock, with warm fluid injection in one borehole and passive temperature measurement in the other.  The experimental results were also simulated using a similar model having a first-type condition at the injection borehole for comparison. The simulations show that the heat transfer coefficient has a significant influence on the shape of the breakthrough curve and allows for an excellent match with the field data, whereas the model with the first-type condition cannot obtain a match of similar quality. </p>

scholarly journals Unsteady Turbine Blade and Tip Heat Transfer Due to Wake Passing

2007 ◽  
Author(s):  
Ali A. Ameri ◽  
David L. Rigby ◽  
Erlendur Steinthorsson ◽  
James Heidmann ◽  
John C. Fabian
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Suction Side ◽  
Significant Difference ◽  
Blade Tip ◽  
Type Boundary ◽  
Type Boundary Condition ◽  
Wake Passing

The geometry and the flow conditions of the first stage turbine blade of GE’s E3 engine have been used to obtain the unsteady three-dimensional blade and tip heat transfer. The isothermal wall boundary condition was used. The effect of the upstream wake of the first stage vane was of interest and was simulated by provision of a “gust” type boundary condition upstream of the blades. A one blade periodic domain was used. The consequence of this choice was explored in a preliminary study which showed little difference in the time mean heat transfer between a 1:1 and 2:3 vane/blade domains. The full three-dimensional computations are of the blade having a clearance gap of 2% the span. Comparison between the time averaged unsteady and steady heat transfer is provided. It is shown that there is a significant difference between the steady and time mean of unsteady blade heat transfer in localized regions. The differences on the suction side of the blade in the near hub and near tip regions were found to be rather significant. Steady analysis underestimated the blade heat transfer by as much as 20% as compared to the time average obtained from the unsteady analysis. As for the blade tip, the steady analysis and the unsteady analysis gave results to within two percent.

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