Key Concepts
Mass Flow Rate
Mass Flow and Energy
Conservation and Mass Flow
Basic
100
No observable changes within the control volume of a hair dryer with respect to time
What is Steady State Operation?
100
What is the Mass Flow Rate Equation?
100
accounts for work associated with rotating shafts, displacement of the boundary, and electrical effects
What is W Dot CV?
100
are accounted for by introducing summations
What are Multiple inlets and exits?
100
is a bulk property, meaning that it is a physical property of a system that does not depend on the system size or the amount of material in the system
What is an intensive property?
200
As a tree grows, its mass increases. Why does this not violate the conservation of mass principle?
Matter can not be created nor destroyed BUT it can be rearranged
200
A laser doppler velocimeter measures a velocity of 8 m/s as water flows in an open channel. The channel has a rectangular cross section of .5 m by .2 m in the flow direction. If the water density is a constant 998 kg/m3, determine the mass flow rate, in kg/s
798.4 kg/s
200
Enthalpy reduces this part of the equation
What is u+PV?
200
Equation of continuity comes from this
What is Conservation of Mass?
200
depends on the amount of matter in a sample. Mass and volume are examples
What is an extensive property?
300
Operation involves state changes with time
What is Transient?
300
Refrigerant 134a exits a heat exchanger through .75 in diameter tubing with a mass flow rate of .9 lb/s. The temperature and quality of the refrigeration are -15 degrees F and .05, respectively. Determine the velocity of the refrigerant, in m/s
14.51 m/s
300
Refrigerant 134a enters the evaporator of a refrigeration system operating at steady state at –4oC and quality of 20% at a velocity of 7 m/s. At the exit, the refrigerant is a saturated vapor at a temperature of –4oC. The evaporator flow channel has constant diameter. If the mass flow rate of the entering refrigerant is 0.1 kg/s, determine
(a) the diameter of the evaporator flow channel, in cm.
(b) the velocity at the exit, in m/s.
(a)1.732 cm
(b) 33.7 m/s
300
The figure provides steady state data for water vapor flowing through a pipe fitting configuration. At each exit, the volumetric flow rate, pressure, and temperature are equal. Determine the mass flow rate at the inlet and exits, each in kg/s
Mass Flow Rate Inlet = 10.35 kg/s
Mass Flow Rate Exit = 5.175 kg/s
300
Term that means constant temperature
What is Isothermal?
400
Three types of Mechanisms of energy transfer for a control volume
What are heat, work, and mass flow?
400
Steam enters a 1.6 cm diameter pipe at 80 bar and 600 degree C with a velocity of 150 m/s. Determine the mass flow rate, in kg/s
.62 kg/s
400
The mass flow rate of steam with pressure of 800 lbf/in^2, temperature of 900 Degree F and velocity of 30 ft/s flowing through a 6-in diameter pipe is most closely.
6.11 lb/s
400
Air enters a horizontal constant diameter heating duct operating at steady state at 290 K, 1 bar, with a volumetric flow rate of .25 m^3/s and exits at 325 K, .95 Bar. The flow area is .04 m^2. assuming ideal gas model with k=1.4 for the air, determine the mass flow rate and the velocity at the inlet and exit
1. .3004 kg/s
2. 6.5 m/s
3. 7.37 m/s
400
Term that means NO heat transfer
What is Adiabatic?
500
If the temperature is constant, internal energy does not change. True or False?
True
500
Air modeled as an ideal gas enters a combustion chamber at 20 lbf/in^2 and 70 degrees F through a rectangular duct, 5 ft by 4 ft. If the mass flow rate of the air is 830,00 lb/h, determine the velocity, in ft/s
113.1 ft/s
500
Air at 600 kPa, 330 K enters a well-insulated, horizontal pipe having a diameter of 1.2 cm and exits at 120 kPa, 300 K. Applying the ideal gas model for air determine at steady state the inlet and exit velocities each in m/s, and the mass flow rate in kg/s.
V exit = 251.73 m/s
V inlet = 55.38 m/s
Mass Flow Rate = .04 kg/s
500
Air enters a horizontal constant diameter heating duct operating at steady state at 290 K, 1 bar, with a volumetric flow rate of .25 m^3/s and exits at 325 K, .95 Bar. The flow area is .04 m^2. assuming ideal gas model with k=1.4 for the air, if the mass flow rate is equal to .3004 kg/s and the inlet and exit velocity are 6.25 m/s and 7.37 m/s respectively. Determine the rate of heat transfer
Q= 10.56 kJ/s
500
Term that means constant volume
What is Isochoric?