Forced-convective boiling coefficient estimation

The forced-convective boiling coefficient will be estimated using Chen s method. 

The forced-convective boiling coefficient will be estimated using Chen s method. With 5% vapor, liquid velocity (for liquid flow in tube alone)... 

The convective boiling coefficient lijc can be estimated using the equations for singlephase forced-convection heat transfer modified by a factor fc to account for the effects of two-phase flow ... 

Chen s method was developed from experimental data on forced convective boiling in vertical tubes. It can be applied, with caution, to forced convective boiling in horizontal tubes, and annular conduits (concentric pipes). Butterworth (1977) suggests that, in the absence of more reliable methods, it may be used to estimate the heat-transfer coefficient for forced convective boiling in cross-flow over tube bundles using a suitable cross-flow correlation to predict the forced-convection coefficient. Shah s method was based on data for flow in horizontal and vertical tubes and annuli. 

Single-phase flow region at the inlet the liquid is below its boiling point (sub-cooled) and heat is transferred by forced convection. The equations for forced convection can be used to estimate the heat-transfer coefficient in this region. 

Heat-transfer coefficients for boiling are usually large compared with those for ordinary convection. Estimate the flow velocity which would be necessary to produce a value of h for forced convection through a smooth 6.5-mm-diameter brass tube comparable with that which could be obtained by pool boiling with AT, = I6.7°C, p = 100 lb/in2 abs, and water as the fluid. See Prob. 9-10 for data on properties. 

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