scholarly journals A Miniaturized 3D Heat Flux Sensor to Characterize Heat Transfer in Regolith of Planets and Small Bodies

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4135
Author(s):  
Manuel Domínguez-Pumar ◽  
Jose-Antonio Rodríguez-Manfredi ◽  
Vicente Jiménez ◽  
Sandra Bermejo ◽  
Joan Pons-Nin
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Heat Flow ◽  
Thermal Environment ◽  
Heat Flux Sensor ◽  
Flux Vector ◽  
Small Bodies ◽  
Heat Flux Vector ◽  
Flux Sensor

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.

PROPERTIES OF HEAT FLUX FUNCTIONS AND A LINEAR THEORY OF HEAT FLUX

1995 ◽  
Vol 09 (09) ◽  
pp. 1113-1122 ◽  
Author(s):  
LIQIU WANG
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Temperature Gradient ◽  
Linear Function ◽  
Linear Theory ◽  
Strain Tensor ◽  
Positive Definiteness ◽  
Positive Definite ◽  
Flux Vector ◽  
Heat Flux Vector

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.

Heat Flux Sensor With Minimal Impact on Boundary Conditions

2003 ◽  
Author(s):  
Arash Saidi ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Heat Flux Sensor ◽  
Inverse Heat Conduction ◽  
Minimal Impact ◽  
Sensor Performance ◽  
Flow Through ◽  
Flux Sensor ◽  
The Ideal

A technique for determining the heat transfer on the far surface of a wall based on measuring the heat transfer and temperature on the near wall is presented. Although heat transfer measurements have previously been used to augment temperature measurements in inverse heat conduction methods, the sensors used alter the heat flow through the surface, disturbing the very quantity that is desired to be measured. The ideal sensor would not alter the boundary condition that would exist were the sensor not present. The innovation of this technique in that it has minimal impact on the wall boundary condition. Since the sensor is placed on the surface of the wall, no alteration of the wall is needed. The theoretical basis for the experimental technique as well as experimental results showing the heat flux sensor performance is presented.

Time-Resolved Heat Transfer Measurements on the Tip Wall of a Ribbed Channel Using a Novel Heat Flux Sensor: Part II — Heat Transfer Results

2006 ◽  
Author(s):  
Sean Jenkins ◽  
Jens von Wolfersdorf ◽  
Bernhard Weigand ◽  
Tim Roediger ◽  
Helmut Knauss ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Flux Sensor ◽  
Internal Cooling ◽  
Time Resolved ◽  
Mean Values ◽  
Cooling Channels ◽  
Ribbed Channel ◽  
Detailed Surface ◽  
Flux Sensor

Measurements using a novel heat flux sensor were performed in an internal ribbed channel representing the internal cooling passages of a gas turbine blade. These measurements allowed for the characterization of heat transfer turbulence levels and unsteadiness not previously available for internal cooling channels. In the study of heat transfer, often the fluctuations can be equally as important as the mean values for understanding the heat loads in a system. In this study comparisons are made between the time-averaged values obtained using this sensor and detailed surface measurements using the transient thermal liquid crystal technique. The time-averaged heat flux sensor and transient TLC results showed very good agreement, validating both methods. Time-resolved measurements were also corroborated with hot film measurements at the wall at the location of the sensor to better clarify the influence of unsteadiness in the velocity field at the wall on fluctuations in the heat flux. These measurements resulted in turbulence intensities of the velocity and heat flux of about 20%. The velocity and heat flux integral length scales were about 60% and 35% of the channel width respectively, resulting in a turbulent Prandtl number of about 1.7 at the wall.

scholarly journals Heat Flux Distribution Near a Crevasse

1963 ◽  
Vol 4 (34) ◽  
pp. 461-465
Author(s):  
C. J. Pings
Keyword(s):  
Heat Flux ◽  
Heat Flow ◽  
Flux Distribution ◽  
Temperature Data ◽  
Flux Vector ◽  
Heat Flux Distribution ◽  
Flow Lines ◽  
Heat Flux Vector ◽  
Graphical Differentiation ◽  
Improved Accuracy

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.

HEAT FLUX SENSOR FOR HEAT TRANSFER INVESTIGATION

1998 ◽  
Author(s):  
Sergey Z. Sapozhnikov ◽  
Vladimir Y. Mitiakov ◽  
Andrei V. Mitiakov
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Flux Sensor ◽  
Flux Sensor

Time-Resolved Heat Transfer Measurements on the Tip Wall of a Ribbed Channel Using a Novel Heat Flux Sensor: Part I — Sensor and Benchmarks

2006 ◽  
Author(s):  
Tim Roediger ◽  
Helmut Knauss ◽  
Uwe Gaisbauer ◽  
Ewald Kraemer ◽  
Sean Jenkins ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Turbine Blades ◽  
Temperature Fields ◽  
Heat Flux Sensor ◽  
Internal Cooling ◽  
Time Resolved ◽  
Flux Measurements ◽  
Working Principle ◽  
Flux Sensor

A novel heat flux sensor was tested which allows for time-resolved heat flux measurements in internal ribbed channels related to the study of passages in gas turbine blades. The working principle of the Atomic Layer Thermopile (ALTP) sensor is based on a thermoelectric field created by a temperature gradient over an YBCO crystal (the transverse Seebeck effect). The sensors very fast frequency response allows for highly time-resolved heat flux measurements up to the 1 MHz range. This paper explains the design and working principle of the sensor, as well as the benchmarking of the sensor for several flow conditions. For internal cooling passages, this novel sensor allows for highly accurate, time-resolved measurements of heat transfer coefficients, leading to a greater understanding of the influence of fluctuations in temperature fields.

Thin-Film Heat-Flux Microsensor for Heat-Transfer Measurement in Micro-Heat Exchangers/Microreactors

2012 ◽  
Author(s):  
Houssein Ammar ◽  
David Hamadi ◽  
Bertrand Garnier ◽  
Ahmed Ould El Moctar ◽  
Hassan Peerhossaini ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchangers ◽  
Measurement Techniques ◽  
Heat Transfer Analysis ◽  
Heat Flux Sensor ◽  
Transfer Measurement ◽  
Heat Transfer Measurement ◽  
Flux Sensor

Heat-transfer analysis in microfluidic devices is of great importance in applications such as micro-heat exchangers and microreactors. This work reports on improvements in temperature measurement techniques, which can be the source of large errors due to their intrusiveness and the unreliability of conventional thermal sensors. Gold thin films were deposited on a borosilicate substrate to realize a 2D heat flux sensor for heat-transfer measurement along the main flow within microchannels. Two applications are shown, one related to micro-heat exchangers and the other to microreactors. For the micro-heat exchanger, the effect of length scale on heat transfer in a straight microchannel was investigated and the validity of macroscale correlations for convective heat transfer was checked for deionized water flowing in microchannels of heights 12 to 52 μm. For the microreactor, the reaction enthalpy of an acid–base reaction measured using the new heat-flux sensor had only a 5% discrepancy from the standard value, showing the efficiency of the new thin-film device.

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