Surface temperature, thermography

Thermography The use of a tube or IR film to determine surface temperatures... 

Recently, such a temperature oscillation was also observed by Zhang et al (27,28) with nickel foils. Furthermore, Basile et al (29) used IR thermography to monitor the surface temperature of the nickel foil during the methane partial oxidation reaction by following its changes with the residence time and reactant concentration. Their results demonstrate that the surface temperature profile was strongly dependent on the catalyst composition and the tendency of nickel to be oxidized. Simulations of the kinetics (30) indicated that the effective thermal conductivity of the catalyst bed influences the hot-spot temperature. 

Fig. 16 Temperature and power profiles for a Biginelli condensation (Scheme 2a) under sealed vessel/microwave irradiation conditions. Shown is the temperature measurement in one reference vessel via an internal gas balloon thermometer (T), the surface temperature monitoring of the eight individual vessels by IR thermography (IR 1-8), and the magnetron power (P, 0-1400 W). Reproduced with permission from [26]...

Another technique utilizing radiation from an object as a means of measuring its temperature is that of thermography, that is, the mapping of surface temperature distributions over extended areas. This is fairly widely used in the medical field for the detection of tumors near the surface of the skin and in industrial applications for detection of hot spots, such as defective insulators on power lines, defects in furnace walls, and areas of heat leaks in buildings. Usually, comparison measurements, rather than the actual determinations of temperature values, are made in thermography. Resolutions of 0.05°C to 0.1 °C are attainable under the best conditions. 

For this virtual test of the furnace, the flow of process fluid inside the pipes was not considered so the outer surface temperature had to be specified based on thermography data and an assumed emissivity of 0.8. To represent the heating of the process fluid traveling through the pipes and its resulting affect on heat transfer, the inlet side was made colder than the outlet side according to process fluid temperature data provided by furnace operators. The four furnace outlets (see Figure 11.17) were assumed to have the same pressure. The refractory wall was assumed to be adiabatic with an emissivity of 0.6. 

In the flash thermography application, the surface temperature change with time is given by... 

Infrared (IR) thermography is a nonintrusive, two-dimensional technique for the whole-field measurement of surface temperature. An infrared scanning radiometer (IRSR) detects the electromagnetic energy radiated in the IR spectral band by the surface of interest and converts it into an electronic signal. For an object whose surface temperature is T, the monochromatic radiation of intensity Ex emitted by the surface can be written using Planck s law as... 

Infrared (IR) thermography is a non-intrusive, two-dimensional technique for the whole-field measurement of surface temperature. An infrared scanning radiometer... 

The infrared thermal imaging is often used to investigate changes in skin surface temperature distribution and to monitor the physiology (Autonomous nervous and microvascular systems) in real time for clinical assessment purposes (Ring Ammer, 2012). Therefore, thermography was used in this experiment. 

The measurement of thermal IR radiation is the basis for noncontact temperature measurement and thermography. Thermal IR radiation leaving a surface (W) is called exitance or radiosity. It can be emitted from the surface, reflected off the surface, or transmitted through the surface. This is illustrated in Fig. 2.4. The total radiosity is equal to the sum of the emitted component (We), the reflected component (Wr) and the transmitted component (Wt). The surface temperature is related to We, the emitted component, only. 

Infrared imaging (thermography) Spot surface temperatures or surface temperature pattern as indicator of physical state of object Used most effectively on refractory and insulation furnace tube inspection. Requires specialized skills and instrumentation is costly Infrequent... 

The large temperature difference of the remarkable borehole, opposite other boreholes and their environment is significant. This high temperature difference is a typical feature for a small wall thickness between borehole and blade surface. For technical reasons, precise eroding of the boreholes is difficult. Due to this, the remaining wallthickness between the boreholes and the blade surface has to be determined, in order to prevent an early failure, Siemens/Kwu developed a new method to determine the wallthickness with Impulse-Video-Thermography [5],... 

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