On a ship with a 7500 kW main engine and 35% thermal efficiency, 70% of the...

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On a ship with a 7500 kW main engine and 35% thermal efficiency, 70% of the total waste heat is discharged through the chimney. It is desired to obtain hot water with a temperature of 90C from the exhaust gas. Distilled water is taken into the boiler at a temperature of 30C. Main machine exhaust gas outlet temperature is 650-C and chimney atmosphere outlet temperature is 210-C. Boiler working order is considered as 2 pass and single stage. Since the pipe body diameter is 90 cm, inner pipe diameter is 10 mm, inner pipe wall thickness is 2 mm and body length is 3 meters; a-) Find the total heat transfer amount. b-) Find the total heat transfer coefficient. c-) Find the number of pipes to be used. (2 pass 1 pipe) NOTE: When calculating the convection coefficient, neglect the area blocked by the inner pipes for the area on the body side. Cp water: 4,18kj/kg.K Cp_air: 1,006kj/kg.K k_inner pipe: 385w/mK k water: 0.65w/mK k_air: 0.026 w/mK Pr_water: 6.7 Pr_air: 0.7 Dynamic viscosity of water: 4.26-10^(-4) Dynamic viscosity of air: 1,85-10^(-4) = I On a ship with a 7500 kW main engine and 35% thermal efficiency, 70% of the total waste heat is discharged through the chimney. It is desired to obtain hot water with a temperature of 90C from the exhaust gas. Distilled water is taken into the boiler at a temperature of 30C. Main machine exhaust gas outlet temperature is 650-C and chimney atmosphere outlet temperature is 210-C. Boiler working order is considered as 2 pass and single stage. Since the pipe body diameter is 90 cm, inner pipe diameter is 10 mm, inner pipe wall thickness is 2 mm and body length is 3 meters; a-) Find the total heat transfer amount. b-) Find the total heat transfer coefficient. c-) Find the number of pipes to be used. (2 pass 1 pipe) NOTE: When calculating the convection coefficient, neglect the area blocked by the inner pipes for the area on the body side. Cp water: 4,18kj/kg.K Cp_air: 1,006kj/kg.K k_inner pipe: 385w/mK k water: 0.65w/mK k_air: 0.026 w/mK Pr_water: 6.7 Pr_air: 0.7 Dynamic viscosity of water: 4.26-10^(-4) Dynamic viscosity of air: 1,85-10^(-4) = I