A cooling coil made of copper tube is immersed in a regulated constant temperature bath held...

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A cooling coil made of copper tube is immersed in a regulated constant temperature bath held at a temperature of 20° C. The liquid flowing through the tube enters at 22° C, and the coil must be sufficiently long to 1.8 Problems 29 ensure the exit liquid sustains a temperature of 20.5° C. The bath is so well stirred that heat transfer resistance at the tube-bath interface is minimal, and the copper wall resistance can also be ignored. Thus, the tube wall temperature can be taken equal to the bath temperature. Use Eq. 1.17 to estimate the required tube length (L) under the following conditions for the flowing liquid: at R Do D P T(z) - T To - Tw 1 kcal/kg C -0.01 m 1 m/s 10³kg/m³ where = exp Nu = h " -0.001 kg/m.s k -1.43 104 kcal/(s. m. K) Since the Reynolds number is in the turbulent range, use the correlation of Sieder and Tate (Bird et al. 1960) to calculate h Nu 0.026 Re0.8 Pr1/3 hD Pr- -2π Rhz U₁ ApCp (D = 2R), Nusselt number Cpt k Prandtl number Reynolds number (a) Modify the problem statement by showing the effect of the tube length on the outlet temperature when the fluid enters the tube at 200C and the bath is held at a constant temperature of 800C. Create a plot that shows the exit fluid temperature and the average fluid temperature as a function of the tube length. Create an Excel program that performs these calculations. Re- (1.17) DUOP μ (b) Assuming that water is the flowing liquid, explain whether or not the fluid physical properties can be assumed to be constant. Support your response with the appropriate calculations. A cooling coil made of copper tube is immersed in a regulated constant temperature bath held at a temperature of 20° C. The liquid flowing through the tube enters at 22° C, and the coil must be sufficiently long to 1.8 Problems 29 ensure the exit liquid sustains a temperature of 20.5° C. The bath is so well stirred that heat transfer resistance at the tube-bath interface is minimal, and the copper wall resistance can also be ignored. Thus, the tube wall temperature can be taken equal to the bath temperature. Use Eq. 1.17 to estimate the required tube length (L) under the following conditions for the flowing liquid: at R Do D P T(z) - T To - Tw 1 kcal/kg C -0.01 m 1 m/s 10³kg/m³ where = exp Nu = h " -0.001 kg/m.s k -1.43 104 kcal/(s. m. K) Since the Reynolds number is in the turbulent range, use the correlation of Sieder and Tate (Bird et al. 1960) to calculate h Nu 0.026 Re0.8 Pr1/3 hD Pr- -2π Rhz U₁ ApCp (D = 2R), Nusselt number Cpt k Prandtl number Reynolds number (a) Modify the problem statement by showing the effect of the tube length on the outlet temperature when the fluid enters the tube at 200C and the bath is held at a constant temperature of 800C. Create a plot that shows the exit fluid temperature and the average fluid temperature as a function of the tube length. Create an Excel program that performs these calculations. Re- (1.17) DUOP μ (b) Assuming that water is the flowing liquid, explain whether or not the fluid physical properties can be assumed to be constant. Support your response with the appropriate calculations.

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a To modify the problem statement we will consider the case where the fluid enters the tube at 20C the bath temperature is 80C and we want to observe ... View the full answer