The article describes the methodology for the determination of ambient temperature for thermovision measurements. The adopted methodology consists in the use of the technical blackbody model. Determining the value of the ambient temperature parameter makes it possible to enhance the accuracy of temperature measurement of objects exposed to strong irradiation using a thermovision camera.
Heat pipes, as passive elements show a high level of reliability when taking heat away and they can take away heat flows having a significantly higher density than systems with forced convection. A heat pipe is a hermetically closed duct, filled with working fluid. Transport of heat in heat pipes is procured by the change of state of the working fluid from liquid state to steam and vice versa and depends on the hydrodynamic and heat processes in the pipe. This study have been focused on observing the impact these processes have on the heat process, the transport of heat within the heat pipe with the help of thermovision. The experiment is oriented at scanning the changes in the surface temperatures of the basic structural types of capillary heat pipes in vertical position.
This article presents the validation process of a brake FE model by means of temperature measured on a special stand using infrared technology. Unlike many other publications, the authors try to show the interaction between measurement technology and numerical modeling rather than only nice, perfectly correlated graphs. Some difficulties in choosing and using validation parameters are also pointed out and discussed. Finally, results of FE analyses are compared with measured data, followed by explanation of applied numerical technology and estimation of validation process effectiveness.
The paper refers to earlier publications of the author, on identification of properties of thermomechanical, chemically hardened core/mold sands. In that earlier period, first version of the original DMA apparatus, produced by a Polish company Multiserw-Morek, was used. The Hot Distortion (HD) study results, published by the author in 2008, referred to phenomena accompanying a thermal shock in real conditions of thermal interaction of a liquid alloy on a mold, in reference to a shock possible to obtain in laboratory conditions, without use of liquid alloy as a heat source, with analysis of solutions applied in the DMA apparatus. This paper presents author’s observations on testing a new, innovative version of the LRu-DMA apparatus, containing a module allowing the Hot Distortion (HD) study. Temperature of specimens achieved in the case of the gas burner heating reaches values definitely above 800°C on the heated side and 610°C on the other side. Using an electric radiator, with maximal temperature of 900°C allows obtaining temperatures in between 225-300°C.
Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.
Modern infrared cameras are constructed with two main types of infrared detectors: photon detectors and thermal detectors. Because of economic reasons, vast numbers of modern thermal cameras are constructed with the use of infrared microbolometric detectors which belong to the group of thermal detectors. Thermal detectors detect incident infrared radiation by measuring changes of temperature on the surface of a special micro-bridge structure. Thermal detectors, like microbolometric detectors on one hand should be sensitive to changing temperature to accurately measure incoming infrared radiation from the observed scene, on the other hand there are many other phenomena that change the temperature of the detector and influence the overall response of the detector. In order to construct an accurate infrared camera, there is a need to evaluate these phenomena and quantify their influence. In the article the phenomenon of self heating due to the operation of the readout circuit is analyzed on an UL 03 19 1 detector. The theoretical analysis is compared with the results of conducted measurements. Measurements with a type SC7900VL thermographic camera were performed to measure the thermodynamic behavior of the UL 03 19 1 detector array.
Convective and radiation heat transfer take place between various objects placed in open air space and their surroundings. These phenomena bring about heat losses from pipelines, building walls, roofs and other objects. One of the main tasks in energy auditing is the reduction of excessive heat losses. In the case of a low sky temperature, the radiation heat exchange is very intensive and the temperature of the top part of the horizontal pipelines or walls is lower than the temperature of their bottom parts. Quite often this temperature is also lower than the temperature of the surrounding atmospheric air. In the case of overhead heat pipelines placed in open air space, it is the ground and sky that constitute the surroundings. The aforementioned elements of surroundings usually have different values of temperature. Thus, these circumstances bring about difficulties during infrared inspections because only one ambient temperature which represents radiation of all surrounding elements must be known during the thermovision measurements. This work is aimed at the development of a method for determination of an equivalent ambient temperature representing the thermal radiation of the surrounding elements of the object under consideration placed in open air space, which could be applied at a fairly uniform temperature of the sky during the thermovision measurements as well as for the calculation of radiative heat losses.