PDF Notes: PIPE ELEMENTS NO

What happens to the temperature of air after passing through a convergent-divergent nozzle?

It decreases.

What happens to the density of air after passing through a convergent-divergent nozzle?

It decreases.

What happens to the Mach number of air after passing through a convergent-divergent nozzle?

It decreases.

What remains unaffected by increasing the temperature source in a Carnot cycle?

Heat rejected.

What remains unaffected by decreasing the temperature sink in a Carnot cycle?

Heat added.

What increases when superheating the refrigerant in a vapor compression cycle with useful cooling?

Heat rejected from condenser.

What decreases when superheating the refrigerant in a vapor compression cycle with useful cooling?

Compressor power.

What decreases when superheating the refrigerant in a vapor compression cycle without useful cooling?

COP.

What increases when superheating the refrigerant in a vapor compression cycle without useful cooling?

Compressor power.

What remains unaffected when superheating the refrigerant in a vapor compression cycle without useful cooling?

Compressor power.

What increases when sub-cooling the refrigerant in a vapor compression cycle at condenser exit?

Refrigerated effect.

What decreases when sub-cooling the refrigerant in a vapor compression cycle at condenser exit?

Mass flow rate.

What increases by raising the vaporizing temperature in a vapor compression cycle?

COP.

What decreases by raising the vaporizing temperature in a vapor compression cycle?

Temperature difference between evaporator and compressor.

What increases by raising the condenser pressure in a vapor compression cycle?

Moisture content after expansion.

What increases if the pressure drop in the condenser increases in a vapor compression cycle?

Heat rejected in the condenser.

What decreases if the pressure drop in the condenser increases in a vapor compression cycle?

Mass flow rate.

What remains unaffected if the pressure drop in the condenser increases in a vapor compression cycle?

Compressor power.

What increases if the pressure drop in the evaporator increases in a vapor compression cycle?

Heat rejected in the condenser.

What decreases if the pressure drop in the evaporator increases in a vapor compression cycle?

COP.

What decreases by lowering the condenser pressure in a Rankine cycle?

Heat rejected.

What decreases by increasing the boiler pressure in a Rankine cycle?

Heat rejected.

What decreases when superheating steam to a higher temperature in a Rankine cycle?

Moisture content at the turbine exhaust.

What increases when superheating steam to a higher temperature in a Rankine cycle?

Condenser pressure.

What decreases when reheating steam before entering the second stage in a Rankine cycle?

Moisture content after expansion.

What increases when the Rankine cycle is modified with regeneration?

Cycle efficiency.

What defines intermediate load in power systems?

Combination of base load and peaking load.

What is the sum of maximum demand over simultaneous maximum demand?

Diversity factor.

What is the efficiency of regenerative feed heating cycle with infinite feedwater heaters?

Carnot cycle.

What type of turbine is used in desalination of seawater?

Back pressure turbine.

What law states that an electric voltage is induced in a conductor when it moves relative to a magnetic field?

Faraday’s law.

What device transfers heat directly to electrical energy using thermionic emissions?

Thermionic generator.

What does the loss in weight of coal at 105°C for 1 hour indicate?

Moisture content.

What is eliminated when heating coal at 950°C for 7 minutes?

Volatile matter and moisture.

What consists of hydrogen and certain hydrogen carbon compounds removed from coal by heating?

Volatile matter.

What is formed when heating coal in an uncovered crucible until completely burned?

Ash.

What is used to produce coke by heating caking coal in a coke oven?

Absence of air.

What is the grindability of standard coal?

100.

What is the major constituent of all natural gases?

Methane.

What are the two types of fans?

Centrifugal and axial.

What is the enthalpy of a substance at a specified state due to its chemical composition?

Enthalpy of formation.

What type of boiler is used for supercritical pressure operation?

Once through-circulation boiler.

What heats the economizer in a water tube boiler?

Outgoing flue gas.

What receives heat partly by convection and partly by radiation?

Pendant superheater.

What is the energy storage medium in regenerative superheaters?

Matrix.

What working fluids does the Stirling cycle use?

Compressible fluids.

What process adds heat during the Stirling process?

Isothermal process.

What is the Brayton cycle also known as?

Joule cycle.

What cycle is applied to vehicle propulsion due to practical characteristics?

Brayton cycle.

What do heat exchangers typically involve?

Energy interaction.

What device converts heat to work?

Heat engines.

What is the objective of a heat pump?

Maintain a heated space at high temperature.

What violates the second law of thermodynamics?

Perpetual motion machine of second kind.

What is a process called if no irreversibilities occur outside the system boundaries?

Externally reversible.

What is an energy interaction not accompanied by entropy transfer?

Work.

What is turbocharging in engines?

Using exhaust gases to power a compressor.

What device measures small and moderate pressure differences?

Manometer.

What is a vapor with a temperature higher than the saturation temperature?

Superheated vapor.

What is the energy possessed by a moving body due to its momentum?

Kinetic energy.

What is the thermodynamic process where temperature is constant?

Isothermal process.

What is the function of a pump and compressor?

Increase the total energy content of the flow.

What law states that not all energy received as heat can be converted to work?

Second law of thermodynamics.

What is the intensity of pressure measured above absolute zero?

Gage pressure.

What is the ratio of useful horsepower developed by an engine to the heat during the same time?

Brake thermal efficiency.

What is flow work equal to?

Pressure times specific volume.

What form of energy is due to the position or elevation of a body?

Potential energy.

What is another term for constant volume process?

Isochoric.

What is the work done during a reversible adiabatic expansion process in the turbine?

Ideal work.

What does the efficiency of the Carnot cycle depend on?

Temperature.

What is the heat required in a constant pressure process to vaporize a unit mass of liquid?

Latent heat vaporization.

What device measures temperature differences or high temperatures?

Thermocouple.

What is the science concerned with measuring energy and enthalpy?

Calorimetry.

What is the rate of doing work per unit time?

Power.

What happens to the cycle thermal efficiency when superheating steam in an ideal Rankine cycle?

It increases.

What is the pressure of refrigerant between the expansion valve and compressor intake in a multi-pressure system?

Low side pressure.