Refrigerant$-22($R$-22)$ boiling at $250$ K flows through a tubular heat exchanger.

Tubes are arranged horizontally with an inner diameter of $0\mathrm{.}0172$ m$.$ The mass

velocity of the R$-22$ is $200$ kg$/$m$2$ s$.$ Heat is supplied by condensing the

fluid outside at $12$C$.$ The hot fluid$-$side heat transfer coefficient, hh$,$ is $5,400$

W$/$m$2$ K$.$ The tube is made of copper, and wall resistance and fouling are

neglected. By the use of both Chen and Shah$$s methods, calculate the

following:

a$.$ the convection heat transfer coefficient for R$-22$ for various values of quality

assuming no nucleate boiling

b$.$ heat flux, q$($W$/$m$2)$

c$.$ tube wall temperature $($TWONB$)$ for the ONB.

Is the assumption of no nucleate boiling valid? It may be so at certain values

of xv$.$