Local Shell-Side Heat-Transfer Coefficients in the Vicinity of Segmental Baffles in Tubular Heat Exchangers,

Abstract

Abstract : Local heat-transfer coefficients were studied in detail in the central baffle space between two segmental baffles in a tubular heat exchanger. Two baffle spacings and three flow rates were investigated. baffle spacings and three flow rates were investigated. Average overall Nusselt numbers determined from the measured local coefficients compare favorably with average Nusselt numbers measured by other workers. The data are presented in picture form which enabled the drawing up of a schematic diagram, of the flow pattern in the baffle space. The results indicate the presence of three flow zones between two baffles. The longitudinal-flow zone occurs in the baffle windows. The cross-flow zone and eddy-flow zone occur on the downstream and upstream sides of the baffle space respectively. Heat transfer rates were in general higher in the eddy-flow zone. The heat transfer rate varies along individual tubes from a maximum at the baffle to a minimum midway between the baffle. The minimum value is one-fourth to one-half the value at the baffle.