1) Atmospheric air at 25oC and with a speed of 50 m/s is pumped by a fan over a flat plate.a)What is the minimum plate length in order to achieve a Reynolds number of 108 ?b)At what distance from the leading edge would transition occur if critical Re #= 5x105 ?2) Local Nusselt number is given as Nux=0.04Rex0.9 Pr 1/3. Obtain an expression for,a) average heat transfer coefficient, xb) local heat transfer coefficient, hxc) What is the ratio of the average to local coefficient, x / hx3) Air is in parallel flow over a flat heater surface which is to be maintained at 140oC. Airflow induces a drag force of 0.25 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature? 4) Air at 1 atm with a velocity of 4 m/s and a temperature of 50oC flows over a flat plate that is at a uniform temperature of 100oC. The plate has a length of 0.20 m and a width of 0.1 m.a) What is the average heat transfer coefficient?b) What is the heat transfer rate from plate to the air?c)What is the average friction coefficient and the drag force ?d)What is the heat transfer coefficient at x=0.15 m ? 4)AirU=4 m/sT=50°C-T=100 °Cw=0.1 mL=0.2 mAir at 1 atm with a velocity of 4 m/s and a temperature of 50°C flows over a flat plate that is at a uniformtemperature of 100°C. The plate has a length of 0.20 m and a width of 0.1 m.a) What is the average heat transfer coefficient?b) What is the heat transfer rate from plate to the air?c)What is the average friction coefficient and the drag force ?d)What is the heat transfer coefficient at x=0.15 m ? 311 Heat Transfer Fall1)AirU=50 m/sT=25 °CT-T.XcAtmospheric air at 25°C and with a speed of 50 m/s is pumped by a fan over a flat plate.a)What is the minimum plate length in order to achieve a Reynolds number of 10* ?b)At what distance from the leading edge would transition occur if critical Re #= 5x10° ?0.91/32) Local Nusselt number is given as Nu,=0.04Re,Pr'. Obtain an expression for,a) average heat transfer coefficient, h,b) local heat transfer coefficient, hxc) What is the ratio of the average to local coefficient, h,/ h,x3)AirA=0.25 m2T=15 °CT =140 °CU.=15 m/sFp=0.25 NAir is in parallel flow over a flat heater surface which is to be maintained at 140°C. Airflow induces a drag forceof 0.25 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature?

Question

1)          Atmospheric air at 25oC and with a speed of 50 m/s is pumped by a fan over a flat plate.a)What is the minimum plate length in order to achieve a Reynolds number of 108 ?b)At what distance from the leading edge would transition occur if critical Re #= 5x105 ?2) Local Nusselt number is given as  Nux=0.04Rex0.9 Pr 1/3. Obtain an expression for,a) average heat transfer coefficient, xb) local heat transfer coefficient, hxc) What is the ratio of the average to local coefficient, x / hx3)    Air is in parallel flow over a flat heater surface which is to be maintained at 140oC. Airflow induces a drag force of 0.25 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature?                    4)                 Air at 1 atm with a velocity of 4 m/s and a temperature of 50oC flows over a flat plate that is at a uniform temperature of 100oC. The plate has a length of 0.20 m and a width of 0.1 m.a) What is the average heat transfer coefficient?b) What is the heat transfer rate from plate to the air?c)What is the average friction coefficient and the drag force ?d)What is the heat transfer coefficient at x=0.15 m ? 4)AirU=4 m/sT=50°C-T=100 °Cw=0.1 mL=0.2 mAir at 1 atm with a velocity of 4 m/s and a temperature of 50°C flows over a flat plate that is at a uniformtemperature of 100°C. The plate has a length of 0.20 m and a width of 0.1 m.a) What is the average heat transfer coefficient?b) What is the heat transfer rate from plate to the air?c)What is the average friction coefficient and the drag force ?d)What is the heat transfer coefficient at x=0.15 m ? 311 Heat Transfer Fall1)AirU=50 m/sT=25 °CT-T.XcAtmospheric air at 25°C and with a speed of 50 m/s is pumped by a fan over a flat plate.a)What is the minimum plate length in order to achieve a Reynolds number of 10* ?b)At what distance from the leading edge would transition occur if critical Re #= 5x10° ?0.91/32) Local Nusselt number is given as Nu,=0.04Re,Pr'. Obtain an expression for,a) average heat transfer coefficient, h,b) local heat transfer coefficient, hxc) What is the ratio of the average to local coefficient, h,/ h,x3)AirA=0.25 m2T=15 °CT =140 °CU.=15 m/sFp=0.25 NAir is in parallel flow over a flat heater surface which is to be maintained at 140°C. Airflow induces a drag forceof 0.25 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature?

Accepted Answer

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Atmospheric air at 25oC and with a speed of 50 m/s is pumped by a fan over a flat plate. a)What is the minimum plate length in order to achieve a Reynolds number of 108 ? b)At what distance from the leading edge would transition occur if critical Re #= 5x105 ?