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Surface condition T> Tr0) 45 Luo Tiro) T(ro) T (0) TU A water flow enters the circular tube (right plot) at a uniform temperature T(r,0) that is less than the surface temperature, convection heat transfer occurs and a thermal boundary layer begins to develop. (a) Please explain the requirements (criteria) to reach thermal fully developed condition for both constant surface and heat flux boundary conditions. Ice bath is covering the outer surface of a thick-walled circular Teflon tube (k = 0.5 W/m · K) which has an inner and outer radii of 30 and 50 mm. Water flows through the tube at a rate of m=0.5 kg/s, and its mean inlet and outlet temperatures are Tm,i = 80°C and Tm,o= 20°C. (b) What is the length of the tube if the whole tube is in fully developed region? (c) what is the average convection coefficient associated with the water flow? 1 1 Thermal entrance region Fully developed region Xid, PROPERTIES: Water (Tm=323K): Cp= 4200 J/kg-K, /F550x10-6 kg/s.m, k=0.64 W/m-K, Pr=3