Bypass correction factor, heat

Outside diameter of inner of concentric tubes Inside diameter of outer of concentric tubes Fin efficiency Radiation exchange factor Bypass correction factor, heat transfer Bypass correction factor, pressure drop Leakage correction factor, heat transfer Leakage correction factor, pressure drop Tube row correction factor... 

Bypassing will affect the pressure drop only in the cross-flow zones. The correction factor is calculated from the equation used to calculate the bypass correction factor for heat transfer, equation 12.30, but with the following values for the constant a. 

Using Tinker s approach, BELL(12, i22) has described a semi-analytical method, based on work at the University of Delaware, which allows for the effects of major bypass and leakage streams, and which is suitable for use with calculators. In this procedure, the heat transfer coefficient and the pressure drop are obtained from correlations for flow over ideal tube banks, applying correction factors to allow for the effects of leakage, bypassing and flow... 

In Bell s method the heat-transfer coefficient and pressure drop are estimated from correlations for flow over ideal tube-banks, and the effects of leakage, bypassing and flow in the window zone are allowed for by applying correction factors. 

J h,UJl,Jr Mechanical equivalent of heat Correction factors for baffle bypassing, baffle configuration, baffle leakage, and adverse temperature gradient respectively 1.0(Nm)/J 778(ftlbf)/Btu... 

Heat Transfer Coefficients. In this method, an actual heat transfer coefficient on the shellside hs is determined, correcting the ideal heat transfer coefficient /r.dcai for various leakage and bypass flow streams. The /tldeai is determined for pure crossflow in an ideal tubebank, assuming the entire shellside stream flows across the tubebank at or near the centerline of the shell. The correction factor is defined as a product of five correction factors JUJ2, - J that take into account, respectively, the effects of ... 

The values of "a" for Equation 7.8 are for ideal tube banks with no bypassing or leakage. For well-built tube bundles fabricated to industry-wide accepted standards for clearances (discussed in Chapter 12), the heat transfer coefficients obtained using these values of "a" are normally multiplied by a factor of 0.7 to account for unavoidable bypassing and leakage. However, more precise results can be obtained by using correction factors for the actual conditions as given below. This method assumes that ... 

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