Variable Properties Laminar Gas Flow Heat Transfer and Pressure Drop in Annuli PDF Download

Author: Rex Wayne Shumway
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 217

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Book Description
Results for laminar gas flow in annuli with variation of fluid properties were obtained for both fully developed and uniform entry velocity profiles by solving the appropriate differential equations in finite difference form. The solutions are valid in flow situations where axial conduction may be neglected, and Mach number is low boundary layer assumptions apply and use of the perfect gas equation of state is defensible. All annuli computations were made with a radius ratio of 0.25, which differs sufficiently from the limiting cases of circular tubes and parallel plates to portray geometry well. Numerical results with full variation of the gas properties were obtained. A heating rate was chosen which would lead to peak wall-to-bulk temperature ratios of about three to five and, therefore, significant property gradients. Results are comparable to those found for circular tubes, except fully-established profiles with significant property variation could exist downstream if the unheated wall was held at a constant temperature. In the thermal entry, heat transfer parameters did not differ substantially from constant property predictions. The friction factors and, hence, pressure drop, did vary significantly. With uniform entering velocities these observations were further tempered by dominance of the usual effects of flow development. (Author).