EML 3015C Thermal-Fluids I Fall 1998 Sample Test #1
1. The following figure shows a simple setup of a hydraulic lift with a tank and a weightless piston B . What force is required to support block A, weighs 10,000 N, in a balanced condition as shown. Note that two different liquids, water (r =1000 kg/m3) and oil (r =800 kg/m3), are used in the hydraulic tank.
2. A thin layer of electric heater is sandwiched between two metal plates A and B (both
are 1 m thick and have 1 m2 surface area) as shown. Under steady state
condition, the heater has a temperature of 100° C when 2,000 W
of heat rate is generated inside the heater. Assume the heat transfer only takes place
along the horizontal direction, determine the surface temperature of the plate B. (kA=50
W/m K, h=20 W/m2 K and T¥ = 20° C for both sides)
3. (a) Determine the velocity and mass flow rate of the water being discharged from the bottom hole. The area of the hole is 0.01 m2 which is much smaller than the cross-sectional area of the tank 1 m2. (b) Determine how fast the water level is dropping at this instant, that is to find dh/dt.