scholarly journals Heat Flux Distribution Near a Crevasse

1963 ◽  
Vol 4 (34) ◽  
pp. 461-465
Author(s):  
C. J. Pings

AbstractPreviously reported experimental temperature data were used to compute the two components of the heat flux vector in the ice body adjacent to a crevasse in a glacier of the ice sheet of northern Greenland. Graphical differentiation techniques were employed. The computed components were used to synthesize values of the beat flux vector, including magnitude and direction. Improved accuracy was achieved over the previously reported technique of sketching heat flow lines orthogonal to the isotherms.

1963 ◽  
Vol 4 (34) ◽  
pp. 461-465 ◽  
Author(s):  
C. J. Pings

AbstractPreviously reported experimental temperature data were used to compute the two components of the heat flux vector in the ice body adjacent to a crevasse in a glacier of the ice sheet of northern Greenland. Graphical differentiation techniques were employed. The computed components were used to synthesize values of the beat flux vector, including magnitude and direction. Improved accuracy was achieved over the previously reported technique of sketching heat flow lines orthogonal to the isotherms.


Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4135
Author(s):  
Manuel Domínguez-Pumar ◽  
Jose-Antonio Rodríguez-Manfredi ◽  
Vicente Jiménez ◽  
Sandra Bermejo ◽  
Joan Pons-Nin

The objective of this work is to present the first analytical and experimental results obtained with a 3D heat flux sensor for planetary regolith. The proposed structure, a sphere divided in four sectors, is sensible to heat flow magnitude and angle. Each sector includes a platinum resistor that is used both to sense its temperature and provide heating power. By operating the sectors at constant temperature, the sensor gives a response that is proportional to the heat flux vector in the regolith. The response of the sensor is therefore independent of the thermal conductivity of the regolith. A complete analytical solution of the response of the sensor is presented. The sensor may be used to provide information on the instantaneous local thermal environment surrounding a lander in planetary exploration or in small bodies like asteroids. To the best knowledge of the authors, this is the first sensor capable of measuring local 3D heat flux.


Author(s):  
Jesús García ◽  
Yen Chean Soo Too ◽  
Ricardo Vasquez Padilla ◽  
Rodrigo Barraza Vicencio ◽  
Andrew Beath ◽  
...  

Solar thermal towers are a maturing technology that have the potential to supply a significant part of energy requirements of the future. One of the issues that needs careful attention is the heat flux distribution over the central receiver’s surface. It is imperative to maintain receiver’s thermal stresses below the material limits. Therefore, an adequate aiming strategy for each mirror is crucial. Due to the large number of mirrors present in a solar field, most aiming strategies work using a data base that establishes an aiming point for each mirror depending on the relative position of the sun and heat flux models. This paper proposes a multiple-input multiple-output (MIMO) closed control loop based on a methodology that allows using conventional control strategies such as those based on Proportional Integral Derivative (PID) controllers. Results indicate that even this basic control loop can successfully distribute heat flux on the solar receiver.


2016 ◽  
Vol 103 ◽  
pp. 264-273 ◽  
Author(s):  
Dalong Zhang ◽  
Chenwei Meng ◽  
Hai Zhang ◽  
Pengyuan Liu ◽  
Zhouhang Li ◽  
...  

Author(s):  
D. H. Zhu ◽  
B. Z. Li ◽  
J. G. Yang

This paper studies the heat transfer mechanism in deep grinding process, especially the heat flux to the workpiece. On the basis of triangle moving heat source, a quadratic curve heat flux model in the grinding zone was developed to determine the heat flux distribution and to estimate the surface temperature of workpiece. From the calculated theoretical expression of heat flux to the workpiece, the quadratic curve heat flux can be understood as the superposition of square law heat flux, triangular heat flux and uniform heat flux in the grinding zone. Then four heat flux models using the determined amount of heat flux were applied to estimate the workpiece surface temperatures which were compared with that measured by the embedded thermocouple. It has been found that the quadratic curve heat flux distribution seems to give the best match with measured and theoretical temperature, although square law heat flux model is good enough to predict the temperature.


1995 ◽  
Vol 09 (09) ◽  
pp. 1113-1122 ◽  
Author(s):  
LIQIU WANG

The symmetry and positive definiteness of thermal conductivity tensor K are used to derive some properties of heat flux functions ɸi (i=0, 1, 2). All ɸi are shown to be real-valued. Both ɸ0 and ɸ2 are found to be positive definite, and ɸ1 is constrained between −(ɸ0 + ɸ2) and (ɸ0 + ɸ2). By assuming heat flux vector q to be a linear function of temperature gradient ∇θ and velocity strain tensor D, ɸi reduce to three coefficients which are independent of D and ∇θ.


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