One-Dimensional, Steady-State Conduction Heat Transfer

2017 ◽  
pp. 55-119
Author(s):  
Randall F. Barron ◽  
Gregory F. Nellis
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
One Dimensional ◽  
Conduction Heat Transfer

Analysis of a Transient Asymmetrically Heated/Cooled Open Thermosyphon

1993 ◽  
Vol 115 (3) ◽  
pp. 621-630 ◽  
Author(s):  
G. F. Jones ◽  
J. Cai
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Vertical Plate ◽  
Numerical Study ◽  
Vertical Wall ◽  
Constant Heat Flux ◽  
Closed Form Expression ◽  
Transient Temperature ◽  
Large Reservoir ◽  
One Dimensional

We present a numerical study of transient natural convection in a rectangular open thermosyphon having asymmetric thermal boundary conditions. One vertical wall of the thermosyphon is either heated by constant heat flux (“warmup”) or cooled by convection to the surroundings (“cooldown”). The top of the thermosyphon is open to a large reservoir of fluid at constant temperature. The vorticity, energy, and stream-function equations are solved by finite differences on graded mesh. The ADI method and iteration with overrelaxation are used. We find that the thermosyphon performs quite differently during cooldown compared with warmup. In cooldown, flows are mainly confined to the thermosyphon with little momentum and heat exchange with the reservoir. For warmup, the circulation resembles that for a symmetrically heated thermosyphon where there is a large exchange with the reservoir. The difference is explained by the temperature distributions. For cooldown, the fluid becomes stratified and the resulting stability reduces motion. In contrast, the transient temperature for warmup does not become stratified but generally exhibits the behavior of a uniformly heated vertical plate. For cooldown and Ra > 104, time-dependent heat transfer is predicted by a closed-form expression for one-dimensional conduction, which shows that Nu → Bi1/2/A in the steady-state limit. For warmup, transient heat transfer behaves as one-dimensional conduction for early times and at steady state and for Ra* ≥ 105, can be approximated as that for a uniformly heated vertical plate.

Experimental studies of the propagation of combustion in solids

1992 ◽  
Vol 339 (1654) ◽  
pp. 387-394 ◽  
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Steady State ◽  
Chemical Kinetics ◽  
Profile Analysis ◽  
Numerical Models ◽  
Experimental Studies ◽  
Dimensional Model ◽  
Thermal Methods ◽  
One Dimensional

The application of thermal methods to the study of steady-state combustion is described. Such methods provide a route to information on heat transfer and chemical kinetics which forms a basis for the implementation of numerical models. The experimental results from thermal analysis and temperature profile analysis have been examined within the context of a simple pseudo one-dimensional model of propagation offering some confirmation of the validity of the approach.

Quasi-Steady-State Temperature Distribution in Periodically Contacting Finite Regions

1981 ◽  
Vol 103 (4) ◽  
pp. 739-744 ◽  
Author(s):  
B. Vick ◽  
M. N. O¨zis¸ik
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Steady State ◽  
Temperature Distribution ◽  
Interface Temperature ◽  
Quasi Steady State ◽  
Exact Analytical Solutions ◽  
One Dimensional ◽  
Steady State Temperature ◽  
Regular Cycle

Heat transfer across two surfaces which make and break contact periodically according to a continuous regular cycle is investigated theoretically and exact analytical solutions are developed for the quasi-steady-state temperature distribution for a two-region, one-dimensional, periodically contacting model. The effects of the Biot number, the thermal conductivity and thermal diffusivity of the materials and the duration of contact and break periods on the interface temperature and the temperature distribution within the solids are illustrated with representative temperature charts.

Measurement of Heat Flux From Fires

Volume 4 ◽  
2004 ◽  
Author(s):  
Cecilia S. Lam ◽  
Alexander L. Brown ◽  
Elizabeth J. Weckman ◽  
Walter Gill
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Unit Area ◽  
Inverse Heat Conduction ◽  
Thermal Impact ◽  
Temperature Changes ◽  
One Dimensional ◽  
Conduction Heat Transfer ◽  
Flux Measurements

Heat flux is an important parameter for characterization of the thermal impact of a fire on its surroundings. However, heat flux cannot be measured directly because it represents the rate of heat transfer to a unit area of surface. Therefore, most heat flux measurements are based on the measurement of temperature changes at or near the surface of interest [1,2]. Some instruments, such as the Gardon gauge [3] and the thermopile [2], measure the temperature difference between a surface and a heat sink. In radiation-dominated environments, this difference in temperature is often assumed to be linearly related to the incident heat flux. Other sensors measure a surface and/or interior temperature and inverse heat conduction methods frequently must be employed to calculate the corresponding heat flux [1,4]. Typical assumptions include one-dimensional conduction heat transfer and negligible heat loss from the surface. The thermal properties of the gauge materials must be known and, since these properties are functions of temperature, the problem often becomes non-linear.

Numerical Project for the Undergraduate Heat Transfer Course

2017 ◽  
Author(s):  
Dani Fadda
Keyword(s):  
Heat Transfer ◽  
Solid Body ◽  
Three Dimensional ◽  
Engineering Curriculum ◽  
One Dimensional ◽  
Conduction Heat Transfer ◽  
Heat Transfer Simulation ◽  
The Difference ◽  
Dimensional Simulation ◽  
Classroom Time

A numerical simulation project, described in this paper, was assigned in an undergraduate heat transfer course in the mechanical engineering curriculum. This project complemented the heat transfer lecture course and its corresponding heat transfer lab. It was used to help students visualize and better understand the difference between conduction heat transfer which occurs within a three-dimensional solid body and the convection and/or radiation which occur at the surface of the solid body. It also allowed the students to generate and compare results of one dimensional heat transfer calculations to three dimensional simulation results. The project contained well defined deliverables and an open-ended deliverable which allowed students to be creative. It gave the students reason to discuss the course outside the classroom. It allowed students to use SolidWorks heat transfer simulation and manage a MATLAB script without taking classroom time. It was appreciated and enjoyed by the students.

Heat Transfer Behavior of a Rectangular Thermosyphon Loop

1988 ◽  
Vol 110 (2) ◽  
pp. 487-493 ◽  
Author(s):  
B. J. Huang ◽  
R. Zelaya
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Circulation ◽  
Effective Length ◽  
Dimensionless Group ◽  
Circulation Flow ◽  
One Dimensional ◽  
Dimensional Approximation ◽  
Transfer Behavior ◽  
Geometric Length

The thermal performance of a rectangular thermosyphon loop was studied. The analysis, using a one-dimensional approximation, the conventional friction factor, and an empirical correlation for the overall heat transfer in the cooler, was shown to be able to predict accurately the loop performance at steady state or approaching steady state, if the effective length was used to replace the geometric length in the calculation of loop friction. The steady-state natural circulation flow solution obtained was shown to be a function of a dimensionless group PY or (NuGr/Pr) Y and agrees very well with the experimental results.

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