scholarly journals Discussion: “Combined Geometric and Network Analog Computer for Transient Heat Flow” (Paschkis, Victor, 1959, ASME J. Heat Transfer, 81, pp. 144–149)

1959 ◽  
Vol 81 (2) ◽  
pp. 150
Author(s):  
H. P. Fullerton
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Analog Computer ◽  
Transient Heat Flow

scholarly journals Application of Finite Difference Method for determining lunar regolith diurnal temperature distribution

2018 ◽  
Vol 49 ◽  
pp. 00052 ◽  
Author(s):  
Marcin Kaczmarzyk ◽  
Marcin Gawronski ◽  
Grzegorz Piatkowski
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Lunar Regolith ◽  
In Situ Measurements ◽  
Thermal Boundary Conditions ◽  
Transient Heat Flow

This study was performed in order to verify viability of using finite difference method and proposed simple astrometrical model for modelling heat transfer in lunar regolith. The concept was examined by developing FD model of heat flow for upper 0,9 m of lunar regolith, and comparing obtained results with in situ measurements provided by Apollo 15 and 17 heat flow experiments. The model was based on FDM approximation of Fourier’s law for one dimensional transient heat flow. Both constant and temperature-dependent thermophysical properties of lunar regolith were obtained from in situ measurements. Thermal boundary conditions were assumed on in situ measurements and on remote sensing based analytical model. In order to approximate Sun's position at lunar sky, simple analytical astrometric model of lunar rotation was developed. Matlab 2012a was used to conduct the calculations. Stable solutions were obtained for latitudes between 0 and 80°. Satisfactory agreement between Apollo 15 and 17 in situ measurements and FDM modelling was observed. A conclusion was reached, that both FDM and proposed astrometrical model are to be successfully applied for modelling heat transfer in lunar regolith.

Combined Geometric and Network Analog Computer for Transient Heat Flow

1959 ◽  
Vol 81 (2) ◽  
pp. 144-149 ◽  
Author(s):  
Victor Paschkis
Keyword(s):  
Heat Flow ◽  
Three Dimensional ◽  
Analog Computer ◽  
Transient Heat Flow

A method to analyze three-dimensional transient heat flow is described, which comprises a continuous resistance medium but discrete capacitances. After describing the principles of the technique, the several components and their criteria are discussed, and the accuracy is illustrated by comparing the results of several simple problems with analytically determined values.

Use of analog computer in heat transfer study

SIMULATION ◽  
1972 ◽  
Vol 18 (6) ◽  
pp. 229-229
Author(s):  
Arthur I. Rubin
Keyword(s):  
Heat Transfer ◽  
Analog Computer ◽  
Transfer Study

A Computational Study of the Interaction of Melting Soil With Moisture Transport in the Native Soil

1998 ◽  
Author(s):  
Will Schreiber ◽  
John Kuo
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Moisture Transport ◽  
Moving Boundary ◽  
Computational Study ◽  
Fluid Motion ◽  
Computer Code ◽  
General Purpose ◽  
Simple Method ◽  
Porous Soil

Abstract The current paper describes a computer model designed to analyze the moisture transport in the unmelted, porous soil neighboring a convecting melt. The time-dependent fluid and heat flow in the soil melt is simulated implicitly using the SIMPLE method generalized to predict viscous fluid motion and heat transfer on boundary-fitted, non-orthogonal coordinates which adapt with time. TOUGH2, a general-purpose computer code for multiphase fluid and heat flow developed by K. Pruess at Lawrence Berkekey Laboratory, has been modified for use on time-adaptive, boundary-fitted coordinates to predict heat transfer, moisture and air transport, and pressure distribution in the porous, unmelted soil. The soil melt model is coupled with the modified TOUGH2 model via an interface (moving boundary) whose shape is determined implicitly with the progression of time. The computer model’s utility is demonstrated in the present study with a special two-dimensional study. A soil initially at 20°C and partially-saturated with either a 0.2 or 0.5 relative liquid saturation is contained in a box two meters wide by ten meters high with impermeable bottom and sides. The upper surface of the soil is exposed to a 20°C atmosphere to which vapor and air can escape. Computation begins when the soil, which melts at 1700°C, is heated from one side (maintained at constant temperatures ranging from 1700°C to 4000°C). Heat from the hot wall causes the melt to circulate in such a way that the melt interface grows more rapidly at the top of the box than at the bottom. As the upper portion of the melt approaches the impermeable wall it creates a bottle neck for moisture release from the soil’s lower regions. The pressure history of the trapped moisture is examined as a means for predicting the potential for moisture penetration into the melt. The melt’s interface movement and moisture transport in the unmelted, porous soil are also examined.

scholarly journals Thermal conductivity of sandstones from Biot’s coefficient

Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. D173-D185 ◽  
Author(s):  
Tobias Orlander ◽  
Eirini Adamopoulou ◽  
Janus Jerver Asmussen ◽  
Adam Andrzej Marczyński ◽  
Harald Milsch ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flow ◽  
Cross Section ◽  
Geometric Mean ◽  
Well Log ◽  
Biot’S Coefficient ◽  
Model Predictions ◽  
The Cross ◽  
Rock Texture

Thermal conductivity of rocks is typically measured on core samples and cannot be directly measured from logs. We have developed a method to estimate thermal conductivity from logging data, where the key parameter is rock elasticity. This will be relevant for the subsurface industry. Present models for thermal conductivity are typically based primarily on porosity and are limited by inherent constraints and inadequate characterization of the rock texture and can therefore be inaccurate. Provided known or estimated mineralogy, we have developed a theoretical model for prediction of thermal conductivity with application to sandstones. Input parameters are derived from standard logging campaigns through conventional log interpretation. The model is formulated from a simplified rock cube enclosed in a unit volume, where a 1D heat flow passes through constituents in three parallel heat paths: solid, fluid, and solid-fluid in series. The cross section of each path perpendicular to the heat flow represents the rock texture: (1) The cross section with heat transfer through the solid alone is limited by grain contacts, and it is equal to the area governing the material stiffness and quantified through Biot’s coefficient. (2) The cross section with heat transfer through the fluid alone is equal to the area governing fluid flow in the same direction and quantified by a factor analogous to Kozeny’s factor for permeability. (3) The residual cross section involves the residual constituents in the solid-fluid heat path. By using laboratory data for outcrop sandstones and well-log data from a Triassic sandstone formation in Denmark, we compared measured thermal conductivity with our model predictions as well as to the more conventional porosity-based geometric mean. For outcrop material, we find good agreement with model predictions from our work and with the geometric mean, whereas when using well-log data, our model predictions indicate better agreement.

scholarly journals A study of sensing heat flow through thermal walls by using thermoelectric module

2015 ◽  
Vol 19 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
Noppawit Sippawit ◽  
Thananchai Leephakpreeda
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Thermoelectric Module ◽  
Plane Wall ◽  
Thermal Engineering ◽  
Transfer Coefficients ◽  
Thermoelectric Effects ◽  
Flow Through ◽  
Flow Detection ◽  
Engineering Practices

Demands on heat flow detection at a plane wall via a thermoelectric module have drawn researchers? attention to quantitative understanding in order to properly implement the thermoelectric module in thermal engineering practices. Basic mathematical models of both heat transfer through a plane wall and thermoelectric effects are numerically solved to represent genuine behaviors of heat flow detection by mounting a thermoelectric module at a plane wall. The heat transfer through the plane wall is expected to be detected. It is intriguing from simulation results that the heat rejected at the plane wall is identical to the heat absorbed by the thermoelectric module when the area of the plane wall is the same as that of the thermoelectric module. Furthermore, both the area sizes of the plane walls and the convective heat transfer coefficients at the wall influence amount of the heat absorbed by the thermoelectric module. Those observational data are modeled for development of sensing heat flow through a plane wall by a thermoelectric module in practical uses.

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