Engineering Certification Thermodynamics & Fluid Mechanics Flashcards
6 cards from real Engineering Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Engineering Certification Thermodynamics & Fluid Mechanics flashcards as text
In a heat exchanger, what does the term 'LMTD' stand for?
Answer: Log Mean Temperature Difference
LMTD (Log Mean Temperature Difference) is the logarithmic average of the temperature differences between hot and cold fluids at each end of a heat exchanger.
What is the thermal efficiency of a Carnot heat engine operating between temperatures T_H and T_C?
Answer: η = 1 - (T_C / T_H)
The Carnot efficiency η = 1 - T_C/T_H (using absolute temperatures in Kelvin) represents the maximum possible efficiency for any heat engine operating between those temperatures.
What is the gauge pressure of a fluid if its absolute pressure is 200 kPa and atmospheric pressure is 101.3 kPa?
Answer: 98.7 kPa
Gauge pressure = Absolute pressure − Atmospheric pressure = 200 − 101.3 = 98.7 kPa.
Which dimensionless number characterizes the ratio of inertial forces to viscous forces in a fluid?
Answer: Reynolds number
The Reynolds number Re = ρvL/μ is the ratio of inertial forces to viscous forces and determines the flow regime in fluid systems.
In thermodynamics, what is enthalpy (H) defined as?
Answer: H = U + PV
Enthalpy is defined as H = U + PV, where U is internal energy, P is pressure, and V is volume; it accounts for flow work in open systems.
What is cavitation in fluid systems?
Answer: Formation and collapse of vapor bubbles due to local pressure drop below vapor pressure
Cavitation occurs when fluid pressure drops below the vapor pressure, causing vapor bubbles to form and then violently collapse, damaging pump impellers and pipe walls.