Heat radiator

One design for a low temperature convection furnace shown in Figure 4 utilizes an external circulating fan, heating chamber, and duct system. The fan draws air (or a protective atmosphere) from the furnace and passes through the external heating chamber and back into the furnace past the work. This system minimizes the chance that the work receives any direct heat radiation. In theory it is less efficient because the external blower, heating chamber, and ductwork add external surfaces that are subject to heat losses. 

The cooling air temperature should be measured by several thermometers placed it different points around and halfway tip the motor, at a distance of 1-2 m and protected from heat radiation and dratights. The value to be adopted for the temperature of the cooling air or gas during a test should be the mean of the readings of the thermometers placed as mentioned above, taken at eqtial time intervals during the last quarter of the duration of the test. 

Show the net heating of the atmosphere, on an annual basis, by determining the difference between heat entering the atmosphere and heat radiating to the earth s surface and to space. (See Fig. 17. )... 

Sinee the heatsink performs the vast majority of the heat radiation, it is assumed that all the power flows through all the other thermal elements. 

Burns from heat radiation, or fire engulfment. 

The fire spreads easily by, e.g., running liquid fire, a pool fire, a fire ball, heat radiation or thermal lift (convection). 

F = Fraction of heat radiated. Refer to the last section of this chapter for some appropriate values of F. 

It has also been shown that heat radiation may heat and weaken the containment. The failure of penetration seals due to high temperature has been investigated, but full scale containment failure test have not been done. 

A planar polished surface reflects heat radiation in a similar manner with which it reflects light. Rough surfaces reflect energy in a diffuse manner hence radiation is reflected in all directions. A blackbody absorbs all incoming radiation and therefore has no reflection. A perfect blackbody does not exist a near perfect blackbody surface such as soot reflects 5% of the radiation, making it the standard for an ideal radiator. 

The temperature limits inside a building are mostly within the variations of the temperature outside, and the heat resistance requirements on the building materials inside are the same as the requirements on materials used outside. There could be some additional requirements on outside materials depending on rain, snow, wind, sunshine, etc. When the temperatures inside, whether higher or lower than outside, will be used because of the process, the building materials must be chosen with these requirements taken into account, especially when heat radiation is a factor. This should not be confused with demands on temperature and humidity insulation. 

The emissivity e of the bulb is quite insensitive to the material of the bulb, as long as it is not a polished bright metal. Because the bulb radiates longwave heat radiation, we can use the value e = 0.95. 

Radiometer A sensitive instrument for the measurement of heat radiation. 

The maximum heat radiation that people are exposed to from a flarestack should not exceed 4.7 kW/m (1,500 Btu/ft /hr), about three times the peak solar radiation in the tropics. Even this amount of radiation can be withstood without injury for only a minute or two. The maximum to which people may be exposed continuously is about 1.7 kW/m (500 Btu/ft-/hr). In the neighborhood of flarestacks (say, wherever the radiation could exceed 1.7 kW/m ), the temperatures reached by cables, roofing materials, and plastic equipment should all be reviewed to make sure they cannot be damaged [8, 9]. 

Electrical isolation Heat radiation Cooling coils Recent incidents Vacuum relief valves Accidents at sea Fires Problem sources Emulsion breaking Chimney effects Interlock failure Choosing materials. 

In order to compute the thermal radiation effects produced by a burning vapor cloud, it is necessary to know the flame s temperature, size, and dynamics during its propagation through the cloud. Thermal radiation intercepted by an object in the vicinity is determined by the emissive power of the flame (determined by the flame temperature), the flame s emissivity, the view factor, and an atmospheric-attenuation factor. The fundamentals of heat-radiation modeling are described in Section 3.5. 

A BLEVE can cause damage from its blast wave and from container fragments such fragments can be propelled for hundreds of meters. If the vapor-air mixture is flammable, the BLEVE can form a fireball with intense heat radiation. Each effect is discussed in the following sections. 

The subject of flash fires is a highly underdeveloped area in the literature. Only one mathematical model describing the dynamics of a flash fire has been published. This model, which relates flame height to burning velocity, dependent on cloud depth and composition, is the basis for heat-radiation calculations. Consequently, the calculation of heat radiation from flash fires consists of determination of the flash-fire dynamics, then calculation of heat radiation. 

The heat radiation received by an object depends on the flame s emissive power, the flame s orientation with respect to the object, and atmospheric attenuation, that is... 

This appendix is a summary of the woiit published in the so-called Green Book (1989). Possible effects of explosions on humans include blast-wave overpressure effects, explosion-wind effects, impact from fragments and debris, collapse of buildings, and heat-radiation effects. Heat-radiation effects ate not treated here see Chapter 6, Figure 6.10 and Table 6.6. 

The tlienual radiation intensity and tlie time duration of fires often are used to estimate injury and damage due to a fire. Various tables liave been compiled to set up criteria for fire damage to people and property. Table 7,3.1 shows a relationsliip between heat radiation intensity and bum injury, ... 

The nature of the surrounding population. The distribution of tlie population indoors varies depending on tlie lime of day and the season, tlie overall healtli of the population (senior citizens, infirm, etc.), and tlie type of clothing being worn (cotton, wool, polyester, etc.) by tlie personnel exposed to a possible heat radiation. 

Fire and explosion models describe the magnitude and physical effects (heat radiation, explosion overpressure) resulting from a fire or e.xplosion. 

Hitze-probe, /. heat teat, -strahlung, /. heat radiation, -wirkung, /. action of heat, heat effect, thermal effect, -wirkungsgrad, m. thermal efficiency. 

Another application of the Seebeck effect is to be found ill detectors of small quantities of heat radiation. These sensitive detectors comprise a thermopile, a pile of thermocoup)les (small pieces of two different metals connected in V form and put into series). Half of the junctions of the thermopile are shielded within the detector, whereas the other half are exposed to... 

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