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45 Cards in this Set
- Front
- Back
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(A) What is the basic steam power cycle called? (B) And what is the order in which it runs?
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(A) Rankine Cycle
(B) Turbine - Condenser Water Pump - Boiler |
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What is the order of a Spark Ignition Engine cycle?
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Intake, Compression, Expansion, Exhaust
Remember ICEE! |
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What is a system?
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A system is a specifically identified fixed mass of material separated from its surroundings by a real or imaginary boundary.
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What is a control volume?
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A control volume is a region in space separated from its surroundings by a real or imaginary boundary, the control surface, across which mass and energy my pass.
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What is the difference between a system and control volume?
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A control volume allows mass and energy to enter or exit through it as a system is totally closed off.
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What is the working fluid in an internal combustion engine?
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Air-fuel mixture
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What makes something a cycle?
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Something is only a cycle if it returns to its original state. In the example with the S.I. Engine, different fluid enters the intake everytime.
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(A) What is the conservation law equation? (B) For which three properties can this law be used for?
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(A) Xin - Xout + Xgen = Xstored
(B) Mass, Energy, Momentum |
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What is the instantaneous equation for the conservation law?
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X*in - X*out + X*gen = X*stored where the dots mean it is a time rate.
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What is a property?
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A property is a quantifiable macroscopic characteristic of a system.
Ex. mass, volume, density, pressure, temperature |
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What is a state?
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A thermodynamic state of a system is defined by the values of all of the system thermodynamic properties.
When a system's property changes, the system undergoes a change in state. |
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What is a process?
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A process occurs whenever a system changes from one state to another state.
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What are the different kinds of processes?
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Isothermal, Isobaric, Isentropic.
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What does Isothermal, Isobaric, and Isentropic mean?
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Isothermal - constant temperature
Isobaric - constant pressure Isentropic - constant entropy |
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What is a flow process?
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A flow process occurs whenever the state of the fluid entering a control volume is different from the state of the fluid exiting the control volume.
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What is a cycle?
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A thermodynamic cycle consists of a sequence of processes in which the working fluid returns to its original thermodynamic state.
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In order for a system to be in equilibrium what must it be in?
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Thermal, Mechanical, Phase, and Chemical
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What is a quasi equilibrium process?
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It is a process that happens sufficiently slowly such that departures from thermodynamic equilibrium are always so small that they can be neglected.
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(A)What is a pure substance? (B) What are the three physical phases?
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(A) A pure substance is a substance that has a homogeneous and unchanging chemical composition.
(B) Vapor, Liquid, Solid |
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(A) What is an extensive property?
(B) Examples? |
(A) It depends on how much of the substance is present or the "extent" of the system under consideration.
(B) Volume and Energy, they both depend on size, or mass of system. |
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(A) What is an intensive property?
(B) Examples? |
(A) An intensive property is independent of the mass of the substance or system under consideration. (B) Temperature and Pressure.
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(A) What is the equation for specific volume? (B) Specific energy?
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(A) v = V/M (m^3/kg)
(B) e = E/M (J/kg) These are mass specific properties. |
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(A) What is the molar-specific equations for volume? (B) Energy?
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(A) v) = V/N (m^3/kmol)
(B) e) = E/N (J/kmol) |
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(A) What is the equation for density?
(B) What is the equation for specific volume? |
(A) p = M/V
(B) v = 1/p |
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What is the conversion from bar to pascals to atmosphere?
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1 bar = 10^5 Pa
1 atm = 1.01325 x 10^5 Pa |
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(A) What is the conversion from C to K? (B) C to F? (C) F to C?
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(A) K = C + 273.15
(B) F = (9/5)T(C) + 32 (C) C = (5/9)[T(F) - 32] |
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What does Cv and Cp mean?
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Cv is constant volume specific heat
Cp is constant pressure specific heat |
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What is the state principle?
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In dealing with a simple compressible substance, the thermodynamic state is completely defined by specifying two independent intensive properties.
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What is the ideal gas law?
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Pv = RT
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What is the definition of a particular gas constant?
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Ri = Ru/Mi (J/kg*K)
Ru is the universal constant 8.314 x 10^3 (J/kmol*K) |
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What are the derived equations from the ideal gas law?
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(1) P = pRT
(2) PV = MRT (3) PV = NRuT (4) Pv = RuT |
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Make sure you know what P-v, P-T, and T-v graphs look like.
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REMEMBER
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What is the critical point?
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The critical point is a point in P-v-T space defined by the highest possible temperature and the highest possible pressure for which distinct liquid and gas phases be observed.
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What are the denoted symbols for (A) critical temperature? (B) critical pressure? (C) critical specific volume?
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(A) Tc
(B) Pc (C) Vc |
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How will you know using the critical point if a gas is ideal to use PV = RT or if you have to use the charts?
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If you are given a temperature at some pressure...you put both over their respective critical values. If
P << Pc and T is >> Tc then the gas is exerted to be an ideal gas. |
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(A) What is the equation to define ideal gas behavior? (B) How can this be used?
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(A) Z = Pv/RT
(B) The closer Z is to being 1, the more ideal it becomes. 1 is ideal. |
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Make sure you know how to interpolate!
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REMEMBER!
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What are the three regions of a T-v graph when dealing with a the heating of a chemical?
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From the left to right is the compressed (subcooled), liquid-vapor (saturation), and vapor (superheated).
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What are the two lines that meet at the critical point on a T-v graph?
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The saturated liquid line is on the left of the critical point and the saturated vapor line is on the right of the critical point.
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What is the process in which the T-v graph deals with?
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Isobaric (constant pressure)
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(A) What is the equation for quality? (B) An alternative?
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(A) x = Mvapor/Mmix
(B) x = Mg/(Mg+Mf) |
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(A) What equation can be used to relate quality with other different properties? (B) What properties can be used?
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(A) v = (1-x)Vf + xVg
(B) This can be used for specific volume, enthalpy, energy to name the least. |
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In uniform density cases how is the mass calculated?
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M = S pdV
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What is the equation for mass flow rate?
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m* = pvxA
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What is the equation for volumetric flow rate?
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V* = vxA
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