Calibration of non-ideal thermal conductivity sensors

Kömle, Norbert I.; Macher, W.; Kargl, Günter; Bentley, Mark S.

doi:10.5194/gi-2-151-2013

Cited by 2 publications

(9 citation statements)

References 8 publications

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“…Maybe the reason for this high deviation is that the thermal conductivity value given by the manufacturer is only valid when this thermal grease is applied in a thin contact layer and not in the bulk fluid, as used for our measurements. This fact was already observed in the previous measurements described by Kämle et al (2013).…”

Section: Kerafol Kp96supporting

confidence: 84%

“…Due to the mathematically non-ideal geometry of the LNP03 and the LNP04, it was necessary to calibrate them. The LNP03 sensor has already been calibrated by Kämle et al (2013), but it was done again with an improved measurement set-up, while the LNP04 was calibrated for the first time. The offthe-shelf TP02 thermal conductivity sensor served as a reference.…”

Section: Discussionmentioning

confidence: 99%

“…While the first method has been described in Hütter (2011), Hütter andKämle (2012) and Macher et al (2013), the second method is described in this section. The testing and calibration of the LNP03 sensor were already conducted by Kämle et al (2013) and is now verified by measurements in partly different sample materials and an adapted measurement set-up. Calibration of the LNP04 sensor was carried out in the same way.…”

Section: Calibration Of the Lnp Sensorsmentioning

confidence: 92%

“…the heated segment of 66. According to Kämle et al (2013), sensors with a ratio of 60 or more fulfil the requirements for the evaluation based on line heat source theory, so the TP02 sensor meets this requirement. All described dimensions can be found in Fig.…”

Section: Tp02 -Thermal Probe 02mentioning

confidence: 99%

“…As already mentioned in Kämle et al (2013), these sensors are necessarily thicker and shorter and so cannot fulfil the requirements for the evaluation of the thermal conductivity by Eq. (8).…”

Section: Calibration Of the Lnp Sensorsmentioning

confidence: 99%

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Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

Tiefenbacher

Kömle

Macher

et al. 2016

Geosci. Instrum. Method. Data Syst.

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Abstract. The thermal properties of the surface and subsurface layers of planets and planetary objects yield important information that allows us to better understand the thermal evolution of the body itself and its interactions with the environment. Various planetary bodies of our Solar System are covered by so-called regolith, a granular and porous material. On such planetary bodies the dominant heat transfer mechanism is heat conduction via IR radiation and contact points between particles. In this case the energy balance is mainly controlled by the effective thermal conductivity of the top surface layers, which can be directly measured by thermal conductivity probes. A traditionally used method for measuring the thermal conductivity of solid materials is the needleprobe method. Such probes consist of thin steel needles with an embedded heating wire and temperature sensors. For the evaluation of the thermal conductivity of a specific material the temperature change with time is determined by heating a resistance wire with a well-defined electrical current flowing through it and simultaneously measuring the temperature increase inside the probe over a certain time. For thin needle probes with a large length-to-diameter ratio it is mathematically easy to derive the thermal conductivity, while this is not so straightforward for more rugged probes with a larger diameter and thus a smaller length-to-diameter ratio. Due to the geometry of the standard thin needle probes they are mechanically weak and subject to bending when driven into a soil. Therefore, using them for planetary missions can be problematic.In this paper the thermal conductivity values determined by measurements with two non-ideal, ruggedized thermal conductivity sensors, which only differ in length, are compared to each other. Since the theory describing the temperature response of non-ideal sensors is highly complicated, those sensors were calibrated with an ideal reference sensor in various solid and granular materials. The calibration procedure and the results are described in this work.

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Section: Kerafol Kp96supporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Calibration Of the Lnp Sensorsmentioning

confidence: 92%

Section: Tp02 -Thermal Probe 02mentioning

confidence: 99%

Section: Calibration Of the Lnp Sensorsmentioning

confidence: 99%

See 3 more Smart Citations

Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

Tiefenbacher

Kömle

Macher

et al. 2016

Geosci. Instrum. Method. Data Syst.

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show abstract

Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

Tiefenbacher¹,

Kömle²,

Macher³

et al. 2016

Preprint

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Abstract. The thermal properties of the surface and subsurface layers of planets and planetary objects yield important information that allows us to better understand the thermal evolution of the body itself and its interactions with the environment. Various planetary bodies of our Solar System are covered by so-called regolith, a granular and porous material. On such planetary bodies the dominant heat transfer mechanism is heat conduction via IR radiation and contact points between particles. In this case the energy balance is mainly controlled by the effective thermal conductivity of the top surface layers, that can be directly measured by thermal conductivity probes. A traditionally used method for measuring the thermal conductivity of solid materials is the needle-probe method. Such probes consist of thin steel needles with an embedded heating wire and temperature sensors. For the evaluation of the thermal conductivity of a specific material the temperature change with time is determined by heating a resistance wire with a well-defined electrical current flowing through it and simultaneously measuring the temperature increase inside the probe over a certain time. For thin needle probes with a large length-to-diameter ratio it is mathematically easy to derive the thermal conductivity, while this is not so straightforward for more rugged probes with a larger diameter and thus a smaller length-to-diameter ratio. Due to the geometry of the standard thin needle probes they are mechanically weak and subject to bending when driven into a soil. Therefore, using them for planetary missions can be problematic. In this paper the thermal conductivity values determined by measurements with two non-ideal, ruggedized thermal conductivity sensors, which only differ in length, are compared to each other. Since the theory describing the temperature response of non-ideal sensors is highly complicated, those sensors were calibrated with an ideal reference sensor in various solid and granular materials. The calibration procedure and the results are described in this work.

show abstract

Calibration of non-ideal thermal conductivity sensors

Cited by 2 publications

References 8 publications

Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

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