In a falling film evaporator, the inside and outside diameters of the tube wall are $25 \mathrm{~mm}$ and $27 \mathrm{~mm}$, respectively. The tube is made of SS304 (thermal conductivity= $15 \mathrm{~W} \mathrm{~m}^{-1} \mathrm{~K}^{-1}$ ) and the inside convective film coefficient is $750 \mathrm{~W} \mathrm{~m}^{-2} \mathrm{~K}^{-1}$. Outside the tube wall, film coefficient of condensing steam is $7175 \mathrm{~W} \mathrm{~m}^{-2} \mathrm{~K}^{-1}$. Based on the inside area of the tube, the overall heat transfer coefficient is_____________ $\mathrm{W} \mathrm{m}^{-2} \mathrm{~K}^{-1}$

In a falling film evaporator, the inside and outside diameters of the tube wall are $25 \mathrm{~mm}$ and $27 \mathrm{~mm}$, respectively. The tube is made of SS304 (thermal conductivity= $15 \mathrm{~W} \mathrm{~m}^{-1} \mathrm{~K}^{-1}$ ) and the inside convective film coefficient is $750 \mathrm{~W} \mathrm{~m}^{-2} \mathrm{~K}^{-1}$. Outside the tube wall, film coefficient of condensing steam is $7175 \mathrm{~W} \mathrm{~m}^{-2} \mathrm{~K}^{-1}$. Based on the inside area of the tube, the overall heat transfer coefficient is_____________ $\mathrm{W} \mathrm{m}^{-2} \mathrm{~K}^{-1}$

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