The, Fluid, CRE Flashcards
0th Law of Thermodynamics
(Proponent, Definition)
Ralph Howard Fowler
If TA=TB and TB=TC, then TA=TC
1st Law of Thermodynamics
(Proponent, Definition)
Rudolf Julius Emanuel Clausius
-Law of Conservation of Energy
-Energy can’t be created/destroyed, only transformed
-Energy of universe is constant
-The total energy of any system and its surroundings is conserved.
2nd Law of Thermo (Clausius Statement)
(Proponent, Definition)
A device that solely transfers heat from low to high temperature is impossible. Work is required.
2nd Law of Thermo (Kelvin-Planck Statement)
A) Impossible for device to completely convert heat to work (n < 1, and n < n,Carnot), effect to surroundings always exist.
B) Impossible for any device operating on a cycle to receive heat from a SINGLE RESERVOIR ONLY and produce a net amount of work. A hot and cold reservoir are required.
Device violating 1st Law of Thermo
PMM1 - Perpetual motion machine of first kind
Device violating 2nd Law of Thermo
PMM2 - Perpetual motion machine of second kind
How to calculate non reversible entropy?
Entropy is state function. S,rev = S,irrev
3rd Law of Thermodynamics
Walther Hermann Nernst
- S=0 at absolute zero (especially perfect crystals), then S>0 for everything else
Carnot Theorem
Nicolas Sadi Carnot
-n,Carnot = n,max (No engine is more efficient than Carnot engine)
- Any reversible engine between two heat reservoirs is a Carnot Engine
For Carnot engines:
Its efficiency depends only on _____ and not the working substance of the engine.
temperature levels (Tc and Th)
The equation, PV = nRT is best obeyed by gases at
low pressure and high temperature
Compressibility factor of a gas is
a. not a function of pressure
b. not a function of its nature
c. not a function of its temperature
d. unity, if it follows PV = nRT
d. unity, if it follows PV = nRT
Gibbs Free Energy
(Proponent, Equation, Definition)
Josiah Willard Gibbs
G=H-TS
Maximum work by system at P&T=k
Helmholtz Free Energy
(Proponent, Equation, Definition)
Hermann Ludwig Ferdinand von Helmholtz
A=U-TS
Maximum work by system at T=k
Otto Cycle
(Describe, by who, steps)
Ideal Spark Ignition Engine
Nikolaus August Otto
1-2: S=k, +W
2-3: V=k, QH <—- diff from Diesel
3-4: S=k, -W
4-1: V=k, QC
Diesel Cycle
(Describe, by who, steps)
Ideal Compression-Ignition Engine
Rudolf Christian Karl Diesel
1-2: S=k, +W
2-3: P=k, QH <—- diff from Otto
3-4: S=k, -W
4-1: V=k, QC
Rankine Cycle
(Describe, by who, steps)
Ideal Vapor Power Cycle
William John Macquorn Rankine
Steps: PaBaTaC
1-2: S=k, +W (PUMP)
2-3: P=k, QH (BOILER)
3-4: S=k, -W (TURBINE)
4-1: P=k, QC (CONDENSER) <— diff from Gas Power Cycles
A gas turbine cycle consisting of two adiabatic steps and two isobaric steps.
Brayton cycle
A device substantially without moving parts, in which a fuel, such as hydrogen, natural gas, methanol, propane, can be converted directly into twice the quantity of electrical energy that would result from the usual boiler-turbine-generator combination.
fuel cell
Describes the temperature change of a fluid when it is throttled
Joule-Thomson Effect
Explain Joule Thomson Effect
The Joule–Thomson effect is the change in temperature of a gas when it undergoes isenthalpic expansion.
Joule-Thomson experiment is ____
a. isobaric
b. adiabatic
c. isenthalpic
d. both(b) & (c)
d. Adiabatic and Isenthalpic
Process that can be reversed without leaving any trace on the surroundings
Reversible process
Temperature scales with ratios that depend on ratios of heat transfer between a reversible heat engine and the reservoirs.
Absolute temperature scales
Pressure that, if it acted in the piston during the entire power stroke, would do an amount of work equal to that actually done on the piston.
Mean effective pressure
The number of independent variables that must be arbitrarily fixed to establish its intensive state.
Degrees of freedom
Van Laar equation deals with the activity co-efficients in
binary solutions
For a spontaneous process, free energy___ whereas entropy ____
DECREASES whereas the entropy INCREASES
If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the
Clayperon-Claussius equation
“Law of corresponding states” says that
Two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
Out of the following refrigeration cycles, which one has maximum COP ?
a. Air cycle
b. Carnot cycle
c. Ordinary vapor compression cycle
d. Vapor compression with a reversible expansion engine
b. Carnot cycle
Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2 (T1 > T2) is
T2 / (T1 - T2)
Trouton’s ratio of __________ liquids is calculated using Kistyakowsky equation.
non-polar
Activity co-efficient is a measure of the
departure from ideal solution behavior.
Melting of ice exemplifies a/an ____
a. adiabatic process.
b. endothermic reaction.
c. exothermic reaction.
d. process involving a chemical reaction.
endothermic reaction.
If “n” is the order of reaction then unit of rate constant is
A. 1/(time)(concentration)^(n-1)
B. (time)-¹(concentration)^(n-1)
C. (time)^(n-1) (concentration)
D. None of these
1/(time)(concentration)^(n-1)
Variables affecting the rate of homogeneous reactions are __, ___, ___
Pressure, temperature, and composition
Rate determining step in a reaction consisting of a number of steps in series is the ____
slowed step
Equilibrium of a chemical reaction as viewed by kinetics is a ___
Dynamic steady state
Sum of the powers of the concentration terms in the rate equation is called the
A. Order of the reaction
B. Overall order of the reaction
C. Molecularity of the reaction
D. None of these
Overall order of the reaction
__________ explains the equilibrium constant for any chemical reaction.
Law of mass action
Catalysts are used to ___
Catalysts diminish the activation energy of the reaction without altering the products.
A chemical reaction occurs when the energy of the reaction molecules is ____ the activation energy
Equal or more than
Limiting reactant in a chemical reactions decides the ___
conversion
Entropy, which is a measure of the disorder of a system is _____
a. independent of pressure.
b. independent of temperature.
c. zero at absolute zero temperature for a perfect crystalline substance.
d. all (a), (b) & (c)
zero at absolute zero temperature for a perfect crystalline substance.
(3 answers)
Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.
-fugacity
-partial pressure
-activity co-efficient
Gibbs phase rule showed that the degrees of freedom is given by the equation _____. Though this has been presented without proof it is true for ____
F=2+C-P-R
Systems in equilibrium
“The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances”. This is the
Law of Mass Action
(none of these and sagot)
Macroscopic properties of homogeneous system at internal equilibrium can be expressed as a function of its ______.
temperature, pressure, and composition
Recall degrees of freedom
The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.
Gibbs free energy
A nozzle is a device, which
increases kinetic energy and decreases pressure.
For any closed system formed from known amounts of prescribed chemical species, the equilibrium state is completely determined when any two independent variables are fixed.
Duhem’s theorem
Lee/Kesler correlation is only applicable for the following compound
non-polar and slightly polar
Fluid whose viscosity is independent of shear rate
Newtonian
Fluid whose viscosity is independent of shear rate
Newtonian
It is a liquid that does not flow at all until a threshold shear stress is attained.
Bingham plastic
This is the measure of a material’s ability to radiate absorbed
energy.
Emissivity
The work done in a free expansion process is
Zero
Reaction conversion increases with an increase in temperature in the
case of which reaction?
Reversible endothermic
Fugacity and pressure are numerically equal when a gas is:
An ideal gas
The dimensionless number that characterizes the flows of fluid in a conduit.
Reynolds number
Pressure drop is proportional to the 1st power of the velocity
Laminar flow
Roughness has no appreciable effect on the friction factor when flow is ____
Laminar
What is the measure of wall thickness of tubing considering that there is no clear-cut distinction between pipe and tubing?
Schedule number
Effect of temperature to viscosity of gasses
increases with increase in temperature
For an ideal fluid flow, the Reynolds number is
infinity
When a fluid flows through a reducer in a piping system, the velocity at the outlet end is _ the velocity at the inlet.
more than
For pipes that must be broken at intervals for maintenance, the connector used should be a/an
elbow
Which valve is used accurately to regulate the flow of liquids and gases at low flow rates?
needle valve
Potential flow is the flow of
Incompressible fluids with no shear
With increase in molecular weight of the gas, the head developed by a centrifugal compressor will ___
decrease
Priming of a centrifugal pump is done to
Avoid cavitation / chances of separation inside the impeller
Heat capacity is defined as C=dQ/dT. What is the difficulty about the relationship of C to Q which are supposedly state functions?
It is a process-dependent quantity
For a zero-order reaction, the ratio of the volume of a backmix reactor to the volume of a plugflow reactor, for the same reactant conversion and conditions, is:
1
Limitation of UNIFAC
Limitation is that group parameters for a specific estimation IS NOT AVAILABLE
*UNIFAC uses the function groups present on the molecules that make up the liquid mixture to calculate activity coefficient
Closed system that produce the maximum work?
Reversible cyclic process
The difference between the actual property value of a solution and the value it would have as an ideal solution at the same T and P and composition is called
c. Excess
atm to BTU/lbmol R
1.987 BTU/lbmol R
atm to psia ft³ / lbmol R
10.73 psiaft3/ lbmolR
1 ton refrigeration to BTU/min
1 ton refrigeration = 200 BTU/min
Water kinematic viscosity
(cP, Poise, Pas,lb/fts)
1 cP
0.01 Poise
0.001 Pas
6.7310^-4 lb/ft*s
Water heat capacity
J/gK, BTU/lbmR, cal/g*K
4.184 J/gK,
1 BTU/lbmR,
1 cal/g*K
Water density
lbm/ft³, g/cm³, kg/m³, g/mL
62.4 lbm/ft³,
1 g/cm³
1000 kg/m³,
1g/mL
1 hp to lbf*ft/s and W
1 hp = 550 lbf*ft/s = 745.1 W
BTU to lbf*ft
1 BTU = 778 lbf*ft
miles to ft
1 mi = 5280 ft
ft³ to gal
and bbl to gal
1 ft³ = 7.481 gallons
1 bbl = 42 gal
The dimensionless quantity regarded as the ratio of the shear stress to the kinetic energy.
Fanning friction number
Pitot tube measures
local velocity
A popular type of heat exchanger for cooling large quantities of fluid is the
shell and tube heat exchanger
If a heat transfer equipment, dirt or scale may be accounted by introducing resistance called ______
fouling factors
Pipes having diameter 14 inches or more are designated by their ___
Outside diameter
(check steel pipe properties)
High specific speed of a pump implies that, it is a/an __________ pump.
Axial flow
(check pump figure)
Location of vena-contracta in an orifice meter does not depend upon the
Type of orifice
Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.
Smaller than
Molten soap mass is transported by a __________ pump.
Centrifugal
Water hammer in a pipeline results from the _____
Rapid pressure change due to a rapid change in the rate of flow
Schedule number of a pipe, which is a measure of its wall thickness, is given by _____
1000 P’/S
Most commonly used joint in the underground pipe lines is the ______
Sleevejoint
R= Latm/molK
0.08206 Latm/molK
How to do Method if Limiting Density?
CALCU
1. y (P/p) vs x (p)
2. Get y-int: a
3. MW = (a)* RT
How to get Kb or Kf from ∆Hvap/fus?
Trouton’s Rule
kb or kf = RT²MW,solvent/(∆Hvap/fus)
How to get ∆Svap/fus from Tboil/freeze?
Trouton’s Rule
∆Svap/fus= R*[4.5 + ln(Tboil/freeze)]
How to get Hvap/fus given P and T?
- x (1/T) vs y (lnP)
- Reg B — STORE
- B =-Hvap / R —- shift solve
Cutoff ratio
rc= Vmid/Vmin
Expansion ratio
re=Vmax/Vmid
Compression Ratio
r=Vmax/Vmin
Describe Regnault’s Method
- Get Vwater and m,gas
- Let Vgas = Vwater
- MW= m,water*RT/PV
Falling Sphere Viscometer
v=g(Dp)²(p,particle-p)/18u
Ostwald Viscometer
u=(π∆Pr⁴t)/(8LV)
Osmotic Pressure
i*Molarity *RT
The reaction in which rate equation corresponds to a stoichiometric equation is called
elementary reaction
There is no correspondence between stoichiometry and rate equation in a ___ reaction
non-elementary
If the rate of reaction independent of the concentration of the reactants, the reaction is said to be?
zero order
Half-life period of a chemical reaction is
the time required to reduce the concentration of the reacting substance to half its initial value
Higher free energy of activation of chemical reaction (at a given temperature) implies ___
Slower rate of reaction
(higher E=lower k=lower rA)
The rate constant of a reaction is a function of ____
Temperature of the system
With increases in temperature, the rate constant obeying Arrhenius equation _____
Decreases exponentially with temperature
Temperature Sensitivity:
Reactions with HIGH activation energy (E) are ____
While reactions with LOW activation energy (E) are ____
high E: very temperature sensitive
low E: low temperature sensitivity
(Look at Arrhenius Eq: lnk/k=-E/R(1/T-1/T)
Temperature Sensitivity:
Reactions are much more sensitive at _____ than _____
more sensitive at LOW-TEMP region than HIGH-TEMP region
__________ explains the mechanism of catalysis.
Activated complex theory
The equilibrium constant of a chemical reaction ____ in the presence of catalyst
emains unaffected in the presence of a catalyst
A batch reactor is characterized by ____
a. constant residence time
b. uniformly mixed
c. ideal with liquid phase reactions
A plug-flow/tubular reactor is characterized by _____
a. presence of LATERAL mixing
b. no longitudinal mixing
c. equal radial velocity
A continuously stirred tank reactor is characterized by ___
a. uniformly mixed
b. continuous flow
Recycling the products of CSTR affects the conversion in what way?
Does NOT change the conversion
A backmix reactor is ____
is same as ideal stirred tank reactor
An autoclave is ___
is a high pressure batch reactor
In a semi-batch reactor ____
Velocity of reaction can be controlled
Conversion ___ with increase in T in case of a reversible endothermic reaction
Increases
A space velocity of 5/hour means that
five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour
A space-time of 3 hours for a flow reactor means that
the time required to process one reactor volume of feed (measured at specified conditions) is 3 hours.
The reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction.
autocatalytic
Steel Pipe Relative Roughness
E=0.00015 ft or 0.045732 mm
Bernoulli mechanical energy balance neglects _____
mechanical energy and friction
Any reversible engine between two heat reservoirs is a _____
Carnot engine
Difference between polytropic and adiabatic processes
Polytropic processes have heat transfer
Process involving fluid flow through a restriction such as an orifice, partially closed valve or porous plug without appreciable change in kinetic and potential energy
Throttling process
Equipment that involves converting internal energy of high velocity stream into kinetic energy, which in turn converts into shaft work
Turbines
The role of turbines is to convert ___ energy into ___ energy
internal energy into kinetic energy
They are vital for the transport of fluids, for fluidization of particulate solids, for bringing fluids to the proper pressure for reaction or processing, etc.
Fluid Movers:
Compressors, pumps, fans, blowers, and vacuum pumps
Rotating equipment that move liquids
Pumps
A homogeneous region of matter.
Phase
Gibbs phase rule is only applicable for _____
systems in equilibrium
When can we say a process is reversible?
Its direction can be reversed at any point by an infinitesimal change in external conditions
Entropy is essential gor chemical engineers to dictate the ____ and ____ of a process
Direction and Quality
The highest temperature and pressure at which a pure chemical specie is observed to exist in vapor/liquid equilibrium
Critical point
Degrees of freedom in triple point
F= 0 (invariant)
Fluids in which their volume expansivity (B) and isothermal compressibility (k) is ZERO
Incomprehensible fluids
“Equations which give property changes such as dU, dH, ∆U and ∆H are valid for ideal gases regardless if the process is reversible or not”
Wala lang, remember this lang
______ do not conform to the same corresponding states behavior as do normal fluids
Quantum gases (H, He, and Ne)
The generalized virial coefficient correlation is only valid for _____
low to moderate pressures
Used to determine the flow of a fluid from a hole in a tank in the size of a point.
Torricelli’s Equation
Why are Cubic equations of states most commonly used?
“They offer a compromise between generality and simplicity that is suitable to represent both vapor and liquid behavior”
Describe the three volume roots of Cubic equations
Largest: Vapor-like
Smallest: Liquid-like
Middle: Not significant
Water Heats of Vaporization and Fusion
∆Hvap=540 cal/g
∆Hfus=80 cal/g
The ______ of elementary reactions is the number of molecules involved in the reaction
Molecularity
Who described temperature as “the state of the body considered ability to communicate heat to the other body”?
James Clark Maxwell
In crystallization, what is known as the formation of nuclei attributable to the existence of macroscopic crystals in the magma?
Secondary nucleation
Limiting condition of ideal gas condition
P —> 0
In the absence of molecular interactions, the internal energy depends on _____
Temperature only
Which of the following is the this is for Bernoulli’s law for fluid flow?
Principle of conservation of energy
For newtonian fluids the shear stress is _____
a linear function of the shear stress of deformation
When pipe joints have to be broken from time to time for maintenance work the connection that should be used is ____
flanges
Which of the following has the best insulting property?
window glass
wood
air
concrete
air
a theoretical body works of safety vit e and m cbt is independent of the wavelength of a special region of irradiation and the surface in motion is called ____
gray body
A popular types of heat exchangers for cooling large quantities of liquid is the ____
shell and tube heat exchanger
Which among the following is most suitable for very high-pressure gas phase reactions?
Tubular flow reactor
The sole connection between an actual process and an imagined hypothetical reversible process employed for determining ideal work is that _________________.
they both apply to the same changes of state.
(Recall irreversible entropy change)
Where do lost work came from? What is the engineering significance?
Entropy generation = W,lost = energy unavailable to do work
Minimize irreversibility = minimize work lost
“The engineering significance of this result is clear: The greater the irreversibility of a process, the greater the rate of entropy production and the greater the amount of energy made unavailable for work. Thus, every irreversibility carries with it a price. Minimizing entropy production is essential for conservation of the earth’s resources.”
How is Third Law of Thermo used to calculate entropies?
Entropy of elements at 0K is measured in their crystalline form
What is the greatest practical value of ideal gas properties?
It provides the base for calculation of real-gas properties.
System for prediction of non-electrolyte activity in non-ideal mixtures
UNIFAC method
A valve that controls flow by means of a disk or wedge-shaped dam sliding at right angles to the direction of flow and seating lightly in the valve body
gate valve
The equation that relates friction factor and Reynold’s number f=64/Re, holds to ___
laminar flow only
The pressure drop in a rotameter is ____ .
constant
When pipe joints have to be broken from time to time for maintenance work, the connection that should be used is ____
flanges
Which of the following produces maximum pressure difference for transportation of gases?
compressors
A device for increasing the velocity of a fluid in steady flow is a ____
nozzle
For Newtonian fluids, the shear stress is ___
a linear function of the shear rate of deformation
Basis for Bernoulli’s law for fluid flow
principle of conservation of energy
Which fitting is used to connect pipes of different diameters?
reducer
A machine or device for moving incompressible fluid is commonly known as ____
pump
Dietus-Boelter equation for determination of heat transfer co-efficient is valid for ____
for fluids in turbulent flow
Accounts for additional resistance to heat flow
Fouling factor
An insulator should have ___
low thermal conductivity
A popular type of heat exchanger for cooling large quantities of fluid is the _____
shell and tube
The rate of evaporation at a given operating temperature in an evaporator is more when ___
the operating pressure is low
Refers to the measure of a fluid’s sensitivity to changes in viscosity with changes in temperature
viscosity index
The most economical valve for use with large diameter pipes.
butterfly
The pressure drop through a gate valve is lowest when ___
fully open
A mechanical pressure gauge which indicates pressure by the amount of deflection under internal pressure of an oval tube bent in an arc of a circle and closed at one end.
Bourdon-tube gauge
A device in which the kinetic energy of one fluid (primary fluid) is used to pump another fluid (secondary fluid).
ejector
What device is used to protect the pipe line from bursting due to pressure rise when the water in the pipe line is brought to rest?
surge tank
What do you call the power required to deliver a given quantity of a fluid against a given head with no losses in the pump?
hydraulic power
A type of valve which permits only one direction of flow.
check valve
Bear pump is ___
A. is a positive displacement pump
B. is a non-positive displacement pump
C. is a centrifugal pump
D. can be started with delivery valve closed
A. is a positive displacement pump
An ideal surface that absorbs all incident radiation regardless of wavelength and direction and is also considered as a perfect emitter is referred to as a _____
black body
