Question

estion 9 10 points Saver Engine oil at 80'C flows over a 5-m-long flat plate whose temperature is 30°C with a velocity of 5.5 m/s. The properties of engine oil at the film temperature of (Ts + T-y2 = (80+ 30y2 = 55°C are p =367 kg/m2, v = 7.045 105 m2/s, k = 0.1414 W/m.*C, and Pr = 1551. Determine the Heat Transfer in kW

Answer 1

Now put the value of Nu im in ③ we get - 0.1414 4683.84 hx 5 lha132.46 w/ mere Now put value of his er we get no Let the depth of heat transfer (a)= h Al Is Tow) Plate is Imo here Area of 9 9 - 132.46*5*(30-80) platel A): 5m x 1m &q= - 33115 watt de here negative sign represents heat transfer is taking from oil to plate. so magnitude of heat transfer is [2 = 33.115 kW Assi I & 5 me

V Giren doto Temperature of engine al (T) = 800 - 353k length of plate (4)=5m. Campesture of plate (Is) = 30c= 300k reity of fluid (v) = 5.5 m/8. ilm temperature (Ist Ta) = (80 +30) = 556 = 328 density (9) = 867 kg 1 m3 tie riscosity (0) = 7.045 x105 mets mal conductivity (K) = 0.1414 w/moc Prand H No (Pr) = 1551 VL 5.585 We know that heat transfer (9) = h Al Is-Tas) - To find h . since Nusselt No (Nu) 2 - and Nusselt Number calculation depands upon value of Reynold's No. , so Reynold's No (Re)= v1 = 5.5x5 - 3.9x15 since Reynolds Number is less than 5x10 so the flow is laminar. so for Laminar flow, NU = 0.664 RoS 0.33 No = 0.664 x ( 3 9 15 30 ( 1551 Nu=4683-84