scholarly journals HEATING AND HEATING 2. A Program Description of a Generalized Heat Transfer Code for Solution of Transient and/or Steady-State Problems in One, Two, or Three Dimensional Cartesian or Cylindrical Coordinate Systems.

1968 ◽  
Author(s):  
R.D. Brunell
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Three Dimensional ◽  
Coordinate Systems ◽  
Cylindrical Coordinate ◽  
Program Description

Verification of Finite Volume Computations on Steady-State Fluid Flow and Heat Transfer

2001 ◽  
Vol 124 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J. Cadafalch ◽  
C. D. Pe´rez-Segarra ◽  
R. Co`nsul ◽  
A. Oliva
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Finite Volume ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Independent Solution ◽  
Post Processing ◽  
Square Duct ◽  
Flow And Heat Transfer

This work presents a post-processing tool for the verification of steady-state fluid flow and heat transfer finite volume computations. It is based both on the generalized Richardson extrapolation and the Grid Convergence Index GCI. The observed order of accuracy and a error band where the grid independent solution is expected to be contained are estimated. The results corresponding to the following two and three-dimensional steady-state simulations are post-processed: a flow inside a cavity with moving top wall, an axisymmetric turbulent flow through a compressor valve, a premixed methane/air laminar flat flame on a perforated burner, and the heat transfer from an isothermal cylinder enclosed by a square duct. Discussion is carried out about the certainty of the estimators obtained with the post-processing procedure. They have been shown to be useful parameters in order to assess credibility and quality to the reported numerical solutions.

Heat Transfer Normal to Paired Arterioles and Venules Embedded in Perfused Tissue During Hyperthermia

1988 ◽  
Vol 110 (4) ◽  
pp. 277-282 ◽  
Author(s):  
C. K. Charny ◽  
R. L. Levin
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Three Dimensional ◽  
Numerical Data ◽  
Tissue Temperature ◽  
Three Dimensional Model ◽  
Sources And Sinks ◽  
The Mean ◽  
Krogh Cylinder ◽  
Subsequent Incorporation

A numerical model of the heat transer normal to an arteriole-venule pair embedded in muscle tissue has been constructed. Anatomical data describing the blood vessel size, spacing, and density have been incorporated into the model. This model computes temperatures along the vessel walls as well as the temperature throughout the tissue which comprises an infinitely long Krogh cylinder around the vessel pair. Tissue temperatures were computed in the steady-state under resting conditions, while transient calculations were made under hyperthermic conditions. Results show that for both large- (1st generation) and medium-sized (5th generation) vessel pairs, the mean tissue temperature within the tissue cylinder is not equal to the mean of the arteriole and venule blood temperatures under both steady-state and transient conditions. The numerical data were reduced so that a comparison could be made with the predictions of a simple two-dimensional superposition of line sources and sinks presented by Baish et al. [1]. This comparison reveals that the superposition model accurately describes the heat transfer effects during hyperthermia, permitting subsequent incorporation of this theory into a realistic three-dimensional model of heat transfer in a whole limb during hyperthermia.

Numerical Simulation of the Fluid Flow and Heat Transfer Processes During Scavenging in a Two-Stroke Engine Under Steady-State Conditions

1992 ◽  
Vol 114 (2) ◽  
pp. 383-393 ◽  
Author(s):  
M. de Castro Gouveia ◽  
J. A. dos Reis Parise ◽  
A. O. Nieckele
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steady State ◽  
Swirling Flow ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Uniform Wall Temperature ◽  
Piston Head ◽  
Bottom Dead Center ◽  
Comparison Of The Results

A numerical simulation of the scavenging process in a two-stroke flat-piston model engine has been developed. Air enters the cylinder circumferentially, inducing a three-dimensional turbulent swirling flow. The problem was modeled as a steady-state axisymmetric flow through a cylinder with uniform wall temperature. The steady-state regime was simulated by assuming the piston head fixed at the bottom dead center. The calculation was performed employing the k–ε model of turbulence. A comparison of the results obtained for the flow field with available experimental data showed very good agreement, and a comparison with an available numerical solution revealed superior results. The effects of the Reynolds number, inlet port angles, and engine geometry on the flow and in-cylinder heat transfer characteristics were investigated. The Nusselt number substantially increases with larger Reynolds numbers and a smaller bore-to-stroke ratio. It is shown that the positioning of the exhaust valve(s) is the main parameter to control the scavenging process.

Thermofluidic Characteristics of a Porous Ventilated Brake Disk

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
H. B. Yan ◽  
T. Mew ◽  
M.-G. Lee ◽  
K.-J. Kang ◽  
T. J. Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Substantial Reduction ◽  
Three Dimensional ◽  
Cooling Capacity ◽  
Vehicle Speed ◽  
Brake Disk ◽  
Cooling Flow ◽  
Flow Mixing ◽  
Bulk Diamond

We introduce a new class of ventilated brake disk which incorporates an open cellular core: wire-woven bulk diamond (WBD). Transient and steady-state thermofluidic characteristics are presented. As reference, a commercially available pin-finned brake disk is also considered. At a braking power of 1.9 kW, representative of a medium sized truck descending a 2% gradient at a vehicle speed of 40 km/h (i.e., 200 rpm), the WBD cored brake disk reduces the overall brake disk temperature by up to 24% compared to the pin-finned brake disk. Results also reveal that in typical operating ranges (up to 1000 rpm), the WBD core provides up to 36% higher steady-state overall cooling capacity over that obtainable by the pin-finned core. In addition, the three-dimensional morphology of the WBD core gives rise to a tangentially and radially more uniform temperature distribution. Although the WBD core causes a higher pressure drop, this is balanced by the benefit of a stronger suction of cooling flow. Flow mixing in an enlarged heat transfer area by the WBD core is responsible for the substantial heat transfer enhancement. The WBD core is mechanically strong yet light while providing a substantial reduction in a brake's operating temperature.

scholarly journals Theoretical fractional formulation of a three-dimensional radio frequency ion trap (Paul-trap) for optimum mass separation

2021 ◽  
pp. 146906672110267
Author(s):  
Sarkhosh Seddighi Chaharborj ◽  
Shahriar Seddighi Chaharborj ◽  
Zahra Seddighi Chaharborj ◽  
Pei See Phang
Keyword(s):  
Laplace Equation ◽  
Ion Trap ◽  
Three Dimensional ◽  
Paul Trap ◽  
Cantor Sets ◽  
Mass Separation ◽  
Coordinate Systems ◽  
Trapping Voltage ◽  
Cylindrical Coordinate ◽  
The Stability

We investigate the dynamics of an ion confined in a Paul–trap supplied by a fractional periodic impulsional potential. The Cantor–type cylindrical coordinate method is a powerful tool to convert differential equations on Cantor sets from cantorian–coordinate systems to Cantor–type cylindrical coordinate systems. By applying this method to the classical Laplace equation, a fractional Laplace equation in the Cantor–type cylindrical coordinate is obtained. The fractional Laplace equation is solved in the Cantor–type cylindrical coordinate, then the ions is modelled and studied for confined ions inside a Paul–trap characterized by a fractional potential. In addition, the effect of the fractional parameter on the stability regions, ion trajectories, phase space, maximum trapping voltage, spacing between two signals and fractional resolution is investigated and discussed.

scholarly journals Steady-State Three - Dimensional Numerical Simulation of Heat Transfer for Thermal Bridges Assessment

2016 ◽  
Vol 6 (1) ◽  
pp. 17-22
Author(s):  
Silviana Brata ◽  
Carmen Maduta ◽  
S. Pescari
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Flow ◽  
Three Dimensional ◽  
Outer Wall ◽  
Thermal Transmittance ◽  
State Heat ◽  
Thermal Bridges ◽  
Steady State Heat ◽  
Steady State Heat Transfer

Abstract This paper presents a study on using the steady-state three-dimensional heat transfer software HEAT3 for evaluating the heat flow of heat transfer through different elements of the building envelope in order to establish the linear thermal transmittance of the linear thermal bridge. The linear thermal transmittance is obtained according to the one-dimensional steady-state heat transfer calculation formula for the plane walls using the heat flow values obtained through the method specified above. The results presented in this paper are part of a wider study on evaluating the heat transfer through building’s envelope elements by evaluating as accurate as possible the thermal bridges effect of the most common building structures. As a case study, it was considered the steady-state heat transfer through an opaque outer wall of a building considering the thermal bridges for the following elements: outer walls intersection, inner and outer wall intersection and outer wall with intermediate floor intersection.

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