Flashcards
Thermodynamics Definitions
Cards in this deck (53)
- 1Mechanical equilibriumNo change in pressure in a system
- 2Phase equilibrium2 phases in a system - no change in mass of each phase
- 3Chemical equilibriumNo change in chemical composition
- 4Open system (One flow, two flow)Mass and energy can enter and leave
- 5Steady flow processFluid properties at an inlet or outlet remain constant and mass and energy contents of a control volume remain constant
- 6Closed system (Non-flow)A fixed amount of mass and mass cannot pass boundary
Energy can enter and leave - 70th law of thermodynamicsIf two bodies are in thermal equilibrium with a third body, then they are also in thermal equilibrium
- 81st law of thermodynamicsEnergy is neither created nor destroyed, only transferred from one form to another
- 92nd law of thermodynamicsEnergy tends to move from areas of high temperature to areas of lower temperature until thermal equilibrium is reached. Entropy does not decrease
- 10PropertyAny characteristic of a substance that can be observed or measured
Not heat - 11Internal or thermostatic propertyDependent on physical and chemical structure
- 12Intensive propertyProperty independent of mass e.g. temperature and pressure
- 13Extensive propertyDependent on mass
- 14Independent propertyCan be varied without affecting other properties e.g. temperature and pressure
- 15WorkEnergy transfer associated with a force acting through a distance
No mass transfer - 16Pure substanceFixed chemical composition throughout
Can be a mix of two phases or several chemicals - 17Saturated liquidLiquid just about to vaporize
- 18Saturated vapourVapour just about to condense
- 19Saturated liquid-vapour mixtureLiquid and vapour existing at equilibrium
- 20Superheated vapourA vapour which will not condense with a small reduction in heat
- 21Saturation temperatureTemperature at which pure substance starts boiling at a given pressure
- 22Saturation pressurePressure at which a pure substance starts boiling at a given temperature
- 23Critical pointPressure at which the saturated liquid and saturated vapour states are identical
(no flat line on TV graph) - 24AdiabaticProcess that occurs without transfer of heat or mass
System that does not transfer heat or mass between system and surroundings - 25IsothermalChange in system with no change in temperature
- 26IsobaricChange in system with no change in pressure
- 27IsochoricChange in system with no change in volume
- 28IsenthalpicConstant enthalpy
- 29Triple pointPressure and temperature at which three phases exist in equilibrium
(273.16K or 0.01'C for water)
- 30Mechanical energyEnergy in an object due to its motion
Potential + kinetic - 31Thermal energyEnergy that comes from heat and is generated by the movement of particles within a substance
Sensible + latent - 32Internal energySum of all microscopic forms of energy
Sensible + latent + chemical + nuclear - 33h Specific enthalpyLatent heat of vaporisation
Quantity of energy required to vaporize a unit mass - 34QualityRatio of mass of vapour to total mass of liquid + vapour
- 35Specific ____Per unit mass
- 36HeadTotal energy of fluid particles per unit weight
(metre) - 37Potential headGravitational potential energy, due to acceleration due to gravity, per unit
- 38Kinetic/velocity headKinetic energy due to velocity/ flow of fluid per unit weight
- 39Pressure headPressure energy, due to static pressure: internal molecule motion which exerts a force on the walls of a container, per unit weight
- 40Archimedes principleAn object submersed in water will have a bouyancy force equal to the weight of water displaced
- 41Pascal's lawThe pressure in a confined, incompressible liquid is transmitted equally in all directions
Shape of container does not affect pressure, only depth of water
/\P=pg/\h - 42Hydrostatic pressurePressure that is exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity.
- 43Surface dragDrag force due to friction between fluid and surface of body
Shearing force - 44Pressure dragDrag force due to pressure differences in fluid around a body
Normal force - 45HeatThe form of energy that can be transferred between systems as a result of a temperature difference
- 46EnergyThe ability to cause changes
- 47SystemA quantity of matter or a region in space chosen for study
- 48BoundaryThe real or imaginary surface that separates a system from its surroundings
- 49StateCondition of a system described by its properties
- 50Total energySum of all forms of energy in a system
- 51Bernoulli's equation1st law of thermodynamics for a flowing fluid
- 52TemperatureThe amount of heat in a substance
- 53PolytropicPV^n=C
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- Engineering (Thermodynamics) Flashcards on Thermodynamics Definitions, created by Emily Mepsted on 22/04/2017.
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- Emily Mepsted
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