Loads temperature profile

The loads should be on piers so that small, high-velocity burners can be fired underneath. For practically constant temperature under the loads, the base pier height should be 5" to 9" (0.13 to 0.23 m) and the burners fired with constant air. Uniform temperature will result from the fact that the thin gas blanket will transfer only about one-third as much heat as above the load, so the blanket temperature will fall very slowly as it moves under the load. Therefore, load temperature profile across the furnace and below the load as well as above will be practically flat, leading to less than 10°F ( 5°C) temperature differential throughout the load. 

If the degree of superheat is large, it will be necessary to divide the temperature profile into sections and determine the mean temperature difference and heat-transfer coefficient separately for each section. If the tube wall temperature is below the dew point of the vapour, liquid will condense directly from the vapour on to the tubes. In these circumstances it has been found that the heat-transfer coefficient in the superheating section is close to the value for condensation and can be taken as the same. So, where the amount of superheating is not too excessive, say less than 25 per cent of the latent heat load, and the outlet coolant temperature is well below the vapour dew point, the sensible heat load for desuperheating can be lumped with the latent heat load. The total heat-transfer area required can then be calculated using a mean temperature difference based on the saturation temperature (not the superheat temperature) and the estimated condensate film heat-transfer coefficient. 

The lg control for the STS-51F experiment was conducted post-flight at NASA KSC Life Support Facilities. The loaded PGU s were connected to ground support equipment located in a computer-controlled environmental room. The temperature of the room was maintained such that the PGU s were able to maintain PGC temperature profiles similar to those of flight. The flight time profile also was simulated in the control experiment. 

In subsequent loaded chamber heat penetration studies, penetration thermocouples should be positioned within the container at the previously determined cold spot. The temperature profile of the container should remain constant among different sterilizing chambers, utilizing steam heat as the sterilizing medium. 

Subsequent to the empty chamber studies, maximum load temperature distribution studies should be conducted to determine if the load configuration influences the temperature distribution profile obtained from the empty chamber studies. The thermocouples utilized in the heat distribution studies are distributed geometrically in representative horizontal and vertical planes throughout the sterilizer. The geometric center and corners of the sterilizer should also be represented. An additional thermocouple should be placed in the exhaust drain adjacent to the sensor that controls vessel temperature, if possible. 

Figure 15.22. Temperature profile and elongation of PMDA/TFDB poly(amic acid) film cured under a constant load.

The sterilization process time is determined from the design F value and the product heat transfer data. The sterilization cycle design must be based on the heating characteristics of the load and of containers located in the slowest heating zone of the load. The variation in the rate of heating of the slowest heating zone must be known, so this variation must be determined under fully loaded conditions. The effect of load-to-load variation on the time-temperature profile must also be determined. Then, the statistically worst-case conditions should be used in the final sterilization process design. 

Figure 16 Simulated temperature profiles along a reactor with and without "desorptive" cooling at various times for the oxidation of CO on a Pt catalyst with water vapor desorption from 3A zeolite in a fixed bed comprising equal proportions of catalyst and adsorbent. The solid curves give the simple regenerative behavior and the dotted curves describe the desorptively cooled case. Initial reactor temperature is 125°C, initial adsorbent loading 0.12 kg/kg, inlet CO-concentration 0.2 mol/l, gas loading 6000 h-1.

Dynamic mechanical load on elastomer products is often exerted at small deformations and low deformation rates but over extended time periods. Then part of the mechanical energy is dissipated into heat depending on the value of the loss modulus. As a consequence, a temperature profile is established within the sample. Then the modulus... 

Fig. 1.24. Steady-state, axial temperature profiles for the gasoline reformerin Figure 1.21. (a) High load 33 kWi Hv (b) low load 3 kWlhv ...

FIGURE 7.3 Temperature profiles for polypropylene compounds containing increasing loadings of magnesium oxide filler. (From Hornsby, P.R. and Watson, C.L., Plast. Rubber Process. Appl., 11, 45, 1989. With permission.)... 

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