Stratification rate, temperature

In actuality, temperature cannot be considered constant if the preceding calculation is performed for large altitude differences. In the Standard Atmosphere, temperature decreases at the rate of approximately 6.5°C per 1000 m (3.5°F per 1000 ft) up to an altitude of about 11,300 m (37,000 ft), the lower bound of the stratosphere. At that height, the temperature becomes constant at — 55°C (— 67°F). The constant temperature of the stratosphere greatly inhibits vertical mixing, thus leading to its name (think of stratification). Vertical temperature changes are discussed further in Section 4.2. 

The use of a natural ventilation system assumes temperature stratification throughout the room height. Air close to heat sources is heated and rises as a thermal plume (Fig. 7.105). Part of this heated air is evacuated through air outlets in the upper zone, and part of it remains in the upper zone, in the so-called heat cushion. The separation level between the upper and lower zones is defined in terms of the equality of and G, which are the airflow rate in thermal plumes above heat sources and the airflow supplied to the occupied zone, respectively. It is assumed that the air temperature in the lower zone is equal to that in the occupied zone, and that the air temperature in the upper zone is equal to that of the evacuated air,... 

The flow and return connections will be designed to suit the flow rates and temperature differentials required. The water-return connection will be fitted with either an internal diffuser or a venturi nozzle to assist mixing of the water circulating within the shell and prevent water stratification. The flow connection will incorporate the... 

Therefore the correct setting and maintaining of the rate of flow of the brine is of great importance. To prevent a disturbance of natural stratification of the electrolyte by thermal convection the operating temperature of the electrolyzer should not exceed roughly 35 °C. In order to reduce the solubility of chlorine in the electrolyte it is necessary to keep a high chloride content in the brine. 

Although much work has been performed to improve and develop other methods of sterilization, very little has been accomplished in the field of dry-heat sterilization. The process is time consuming and difficult to control because of the temperature stratification and slow heating rate. Dry heat is still the agent of choice for sterilizing items that might not be adequately penetrated by steam and that will tolerate high temperatures, such as oils, petrolatum, and closed containers. ... 

Hydrology Seepage Water level Water level dynamics Rate of flow Barriers Flood Temperature stratification Drainage dynamics... 

The accidental release of gaseous hydrogen or die spillage of liquid hydrogen leads to the evolution and dispersion of a gas cloud whose shape is influenced by the type and rate of release and by the atmospheric conditions as well as by topography. Liquid hydrogen at 20 K which immediately starts to vaporize upon release, behaves like a heavier-than-air gas in the very first phase ( cold sink effect ). This short phase of negative buoyancy with a reduced heat and mass transfer due to the stable stratification effects is replaced by an enhanced positive buoyancy as soon as, due to continuous air entrainment from outside into the gas cloud, the cloud temperature has been raised to > 22 K. The dilution... 

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