SUGGESTED MINIMUM KNOWLEDGE OF FLUID

MECHANICS AND HEAT TRANSFER FOR FE EXAM

F. ParsiWinona State University

February 25, 20142 Hour Review

http://www.ncees.org/exams/study_materials/fe_handbook/

Exam Composition

• Morning– 120 Questions– 4 hours– 7% Fluid Mechanics

• Afternoon (General Engineering)– 60 Questions– 15% Fluid Mechanics

Define and/or Explain

• density• specific gravity• specific volume• pressure (absolute and gage)• vapor pressure• stress tensor• shear stress• shear rate• viscosity (dynamic and kinematic)• Newtonian and non-Newtonian fluids• dimensional analysis

Fluid Statics

• u-tube manometer calculations• barometer calculations• hydrostatic pressure• force on submerged flat surface• point of application of the force• force on submerged curved surfaces• hydraulic ram• Archimedes's principle buoyancy

Fluid Dynamics

• Reynolds number and its significance• laminar and turbulent flow• velocity distribution• conservation of mass (continuity equation)• Bernoulli equation• head loss• major head loss calculations in pipes• friction factors (Moody and Darcy)• minor head loss calculations in piping systems• pumping power calculation• hydraulic radius• drag coefficient and drag force

Fluid Measurement Devices

• pitot tube

• venturi meters

• orifices

Example 1: Pressure

What is the atmospheric pressure on the planet if the absolute pressure is 100 kPa and a gage pressure is 10 kPa?

1. 10 kPa

2. 80 kPa

3. 90 kPa

4. 100 kPa

Example 2: static Pressure

What is the height of a column of tetrachloride with a specific gravity of 1.56 that supports a pressure of 1 lbf/in2?

1. 0.01 ft

2. 0.12 ft

3. 1.48 ft

4. 1.56 ft

5. 2.31 ft

Example 3: Viscosity

Kinematic viscosity cabn be expressed in which of the following units?

1. m2/s

2. s2/m

3. kg.s2/m

4. kg/s

Example 4: Hydrostatic Pressure

A pressure of 35 kPa is measured 4 m below the surface of an unknown liquid. What is the specific gravity of the liquid?

1.0.09

2.0.89

3.0.93

4.1.85

Example 5: u-tube manometer

The specific gravity of mercury is 13.6, and the specific gravity of glycerine is 1.26. For the manometer shown, calculate the difference in pressure between points A and B.

1.35 kPa

2.42 kPa

3.55 kPa

4.110 kPa

Example 6: U-Tube Manometer

The fluid in a manometer tube is 60% water and 40% alcohol (specific gravity = 0.8). What is the manometer fluid height difference if a 6.2 lbf/in2 pressure difference is applied across the two ends of manometer?

1. 0.92 in2. 15.5 in3. 186 in4. 215 in5. 361 in

Example 7: Fluid Statics

What is the resultant force on the inclined wall?

1.222 kN

2.395 kN

3.503 kN

4.526 kN

Example 8: Fluid Statics

What is the vertical force on the inclined wall?

1.197 kN

2.392 kN

3.486 kN

4.544 kN

Example 9: Hydrostatic Force

A tank is filled with water to a depth of 10 ft. What is the total force on the gate?

1. 560 lbf2. 5400 lbf3. 5620 lbf4. 6000 lbf5. 6240 lbf

Example 10: Buoyancy

A crown is made of an alloy of gold and silver. The crown weighs 1000 g in air and 940 g in water. What percentage of gold was it? Density of gold and silver are respectively 19.3 g/cm3 and 10.5 g/cm3.

1.53.1%

2.67.4%

3.81.2 %

4.91.3%

Example 11: BuoyancyA 24-in-long rod floats vertically in water. It has a 1-in2 cross section and a specific gravity of 0.6. What length L, is submerged?

1. 2.4 in

2. 9.6 in

3. 14.4 in

4. 18.0 in

5. 18.7 in

Example 12: Fluid Dynamics

Consider water flowing through a converging channel as shown and discharging freely into the atmosphere at the exit. What is the gage pressure at the inlet? Assume the flow to be incompressible and frictionless.

1.102 kPa

2.106 kPa

3.113 kPa

4.127 kPa

Example 13: Dimensionless Numbers

A 500-ft-long surface vessel is modeled at 1:50. What speed must the model travel if a 25 mph similarity is desired?

1. 3.54 ft/sec

2. 5.0 ft/sec

3. 5.2 ft/sec

4. 7.07 ft/sec

5. 7.3 ft/sec

Example 14: Hydraulic radius

The hydraulic radius is

1.The mean radius of the pipe

2.The radius of the pipe bend on the line

3.The wetted perimeter of a conduit divided by the area of the flow

4.The cross-sectional fluid area divided by wetted perimeter

Example 15: Hydraulic radius

What is the hydraulic radius of the shown open channel?

1.b/4

2.b/3

3.b/2

4.2b/3

Example 16: Pipe flowA steel pipe with an inside diameter of 25 mm is 20 m long and carries water at a rate of 4.5 m3/h. Assuming the specific roughness of the pipe is 0.00005 m, the water has an absolute viscosity of 1.00 x 10-3 m2/s and a density of 1000 kg/m3, what is the friction factor?

1.0.023

2.0.024

3.0.026

4.0.028

Example 17: Head Loss

What is the expected head loss per mile of closed circular pipe (17-in inside diameter, friction factor of 0.03) when 3300 gal/min of water flow under pressure?

1. 0.007 ft2. 0.64 ft3. 38 ft4. 3580 ft5. 1.9x107 ft

Example 18: Pipe Flow

The transition between laminar and turbulent flow in a pipe usually occurs at a Reynolds number of approximately

1. 900

2. 1200

3. 1500

4. 2100

5. 3900

Example 19: Pumping Power

A pump requires 75 kW to move water with a specific gravity of 1.0 at a certain flow rate to a given elevation. What power does the pump require if the flow rate and elevation conditions are the same, but the fluid pumped has a specific gravity of 0.8?

1.45 kW

2.60 kW

3.75 kW

4.90 kW

Basic Heat Transfer

• Conduction

• Convection

• radiation