Temperature radial

A technique for calculating radial temperature gradients in a packed bed is given by Smith Chemical Engineering Kinetics, McGraw-HiU, New York, 1956). 

The implicit Crank-Nicholson integration method was used to solve the equation. Radial temperature and concentrations were calculated using the Thomas algorithm (Lapidus 1962, Carnahan et al,1969). This program allowed the use of either ideal or non-ideal gas laws. For cases using real gas assumptions, heat capacity and heat of reactions were made temperature dependent. 

Traver.se number temperature factor), (a) The peak gas temperature minus mean gas temperature divided by mean temperature rise in nozzle design, (b) The differenee between the highest and the average radial temperature. 

An important effect in the design of a tubular flow reactor is the development of a radial temperature gradient in a highly exothermic reaction with wall cooling. The temperatures near the tube axis are... 

Airway surfaces, like skin, are continually exposed to the ambient environment. In contrast to skin submucosal vessels, however, w hich shed excess heat by vasodilating when heated and conserve heat by vasoconstricting when chilled, it is unclear how the airway vasculature responds to temperature extremes. Inspiring cold air poses two challenges to conducting airway tissues the risk of tissue injury should inadequate heat reach the airway surface and excessive body heat loss due to increasing the radial temperature gradient. Vasodilation would protect airway tissue but increase heat loss, while vasoconstriction would produce the opposite effect. 

A steady-state heat balance for a plug flow reactor with no radial temperature gradients is given by ... 

The derivation was based on two assumptions. First, we assumed a linear radial temperature gradient within the solution, Second, we computed "T " at the radius at which there were equal volumes of solutions on either side of it. 

GP 2] [R 2] The radial temperature distribution was determined by modeling, using a worst-case scenario (5 Nl h stoichiometric mixture without inert 100% conversion 80% selectivity) [102], The maximum radial temperature difference amounts to approximately 0.5 K. Thus, isothermal behavior in the radial direction can be diagnosed. 

Detailed modelling of the fixed bed production of phthalic anhydride from o-xylene is discussed by Froment and Bischoff (1990), involving both axial and radial temperature profile effects. 

The temperature with large columns may not be homogenous. A mathematical model of the effect of a radial temperature gradient has been developed and validated on octadecyl-packed columns of 11-15 cm diameter... 

Binary liquid metal systems were used in liquid-metal magnetohydrodynamic generators and liquid-metal fuel cell systems for which boiling heat transfer characteristics were required. Mori et al. (1970) studied a binary liquid metal of mercury and the eutectic alloy of bismuth and lead flowing through a vertical, alloy steel tube of 2.54-cm (1-in) O.D., which was heated by radiation in an electric furnace. In their experiments, both axial and radial temperature distributions were measured, and the liquid temperature continued to increase when boiling occurred. A radial temperature gradient also existed even away from the thin layer next to the... 

There may be radial temperature gradients in the reactor that arise from the interaction between the energy released by reaction, heat transfer through the walls of the tube, and convective transport of energy. This factor is the greatest potential source of disparities between the predictions of the model and what is observed for real systems. The deviations are most significant in nonisothermal packed bed reactors. 

A radial temperature measurement consisted of establishing and recording a steady-state temperature profile for a combination of a specific bed length, Reynolds number, and angle of thermocouple cross. A total of four... 

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