A device for performing boiling experiments consist of a copper bar (k = 400 W/m ∙ K), which is exposed to a boiling liquid at one end, encapsulates an electrical heater at the other end, and is well insulated from its surroundings at all but the exposed surface. Thermocouples inserted in the bar are used to measure temperatures at distances of x 1 = 10 mm and x 2 = 25 mm from the surface.

(a) An experiment is performed to determine the boiling characteristics of a special coating applied to the exposed surface. Under steady-state conditions, nucleate boiling is maintained in saturated water at atmospheric pressure, and values of T₁ = 133.7°C and T₂ = 158.6°C are recorded. If n = 1, what value of the coefficient Cs,f is associated with the Rohsenow correlation?

(b) Assuming applicability of the Rohsenow correlation with the value of Cs.f determined from part (a), compute and plot the excess temperature .∆T_e as a function of the boiling heat flux for 10⁵ < q < 10⁶ W/m². What are the corresponding values of T₁ and T₂ for q"_s = 10 6 W/m²? If q"_s were increased to 1.5 x 10⁶ W/m², could the foregoing results be extrapolated to infer the corresponding values of ∆T_e T₁ and T₂?

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Water, T 0° sat Coated surface, T, X1 Thermocouples Copper bar, k T2 Electrical heater 0000