CH 2 Properties of Fluids

For an ideal gas, if the temperature of the gas is 20 degrees Celsius, the volume expansion coefficient is _____.

0.0034

The SI units of kinematic viscosity are _____.

(meter)^2/second

Match the temperature effect on a fluid to the effect it has on a fluid, under conditions not near the freezing point of the fluid.

1) heating = causes the fluid to expand 2) cooling = causes the fluid to contract

Identify the correct statements about the compressibility of a an ideal gas.

1) increases with increasing pressure 2) is equal to its absolute pressure

Match the types of properties in the left column to the appropriate properties in the right column.

1) intensive properties = independent of the mass of the system, such as temperature, pressure, and density 2) extensive properties = values depend on the size of the system, such as total mass, volume, and the total energy

Identify the components of the total energy of a simple compressible system.

1) internal energy 2) potential energy 3) kinetic energy

From the figure, identify the true statements about variation of dynamic viscosity.

1) liquids, in general, are much more viscous than gases 2) viscosities of different fluids differ by several orders of magnitude 3) Dynamic viscosity of common fluids varies with temperature

Identify the units of kinematic viscosity that are used commonly in engineering.

1) m^2/2 2) stoke

Identify some typical effects of cavitation.

1) reduces performance 2) generates annoying vibrations and noise 3) causes damage to equipment 4) erosion of impeller blades

In the context of specific gravity, identify the true statements.

1) specific gravity is also known as relative density 2) specific gravity is a dimensionless quantity

Identify the properties that do not depend on size of a system from the list.

1) specific total energy 2) specific weight 3) temperature

If a substance is assumed incompressible, the property considered as constant is _____.

1) specific volume 2) density

Which of the following best describes specific properties?

1) specific volume (v=V/m) 2) specific total energy (e=E/m) 3) specific properties are extensive properties per unit mass 4) specific properties are independent of the mass of the system

An equation of state relates the _____ of a substance.

1) temperature 2) pressure 3) density

Identify the true statements about variation of dynamic viscosity of common fluids with temperature at 1 atm.

1) the absolute viscosity of crude oil at 0 degrees Celsius is about 0.016 2) There is no drastic change in the dynamic viscosity of mercury with increase in temperature. 3) The dynamic viscosity of castor oil decreases with increase in temperature.

Two plates are placed at a distance of 'l' from each other. A fluid of viscosity 'mu' is filled between the plates, and the area of contact between the plates and the fluid is A. If one plate is fixed and the other plate is moving at a speed of V, identify the steps that are used to calculate the shear force (F) acting on the plates.

1) use the expression F=mu*A*V/l 2) find the velocity gradient as V/l

A fluid has a dynamic viscosity of 50 poise. The viscosity in SI units is given by _____.

5 Ns/m^2 because 1 Ns/m^2 = 1 Pa*s = 0.1 poise

The initial pressure (P1), volume (V1), and temperature (T1) of a fixed mass of an ideal gas are 101.3 kPa, 20 m^3, 310 K respectively. The final pressure (P2) and volume (V2) are 150 kPa and 22 m^3, respectively. Calculate the final temperature (T2) of the system.

504 K because (P1V1)/T1 = (P2V2)/T2

The magnitude of the universal gas constant (Ru) in SI units is _____.

8.314 kJ/(kmol*K)

A large value of coefficient of volume expansion means _____.

A large change in density with temperature.

The inverse of the coefficient of compressibility is called the _____.

Isothermal compressibility

Match the Mach number Ma with the term used to describe the flow.

Ma = 1 Sonic Ma < 1 Subsonic Ma > 1 Supersonic Ma >> 1 Hypersonic

The SI units of dynamic viscosity are _____.

Newton-second/(meter)^2

The speed of sound in a fluid is a function of the thermodynamic _____ of that fluid.

Properties

Vapor pressure is a property of a pure substance and is identical to the _____ of the liquid.

Saturation Pressure (Psat)

Speed of sound is defined as _____.

The speed at which an infinitesimally small pressure wave travels through a medium.

True or False: For incompressible substances, the constant-volume and constant-pressure specific heats are identical.

True

The coefficient of volume expansion is the property of a fluid that represents the _____.

Variation of the density of a fluid with temperature at constant pressure.

In a hydraulic pump system, the liquid pressure drops below the vapor pressure at some locations, and this result in unplanned vaporization. This phenomenon is called _____.

cavitation

In the equation K= -V(dP/dV), K represents the _____. dP is a small change in the pressure exerted on the fluid, V is the volume of the fluid, and dV is a small change in the volume of the fluid. The temperature of the system is held constant.

coefficient of compressibility

In fluid mechanics, the _____ allows us to treat properties as point functions and to assume that the properties vary continually in space with no jump discontinuities.

continuum idealization

The gas constant R is _____ for each gas.

different

For Newtonian fluids, viscosity is _____.

independent of the rate of deformation

What is the flow work?

it is the energy per unit mass needed to move the fluid and maintain flow.

The international (SI) unit of thermal energy is _____.

joule

The energy that a system possesses as a result of its motion is called _____ energy.

kinetic

The pressure of a gas species in a mixture with other gases is the _____ pressure.

partial

Fluids for which the apparent viscosity decreases with the rate of deformation are referred to as _____fluids.

pseudoplastic

The pressure at which a pure substance changes phase, at a given temperature, is called the ___ pressure.

saturation

The weight of a unit volume of a substance is called its _____.

specific weight

The number of properties required to fix the state of a system is given by the _____.

state postulate

A plot of shear stress versus the rate of deformation (velocity gradient) for a Newtonian fluid is a(n) _____.

straight line

The sum of all forms of energy in a system is called the _____ energy.

total

The property that represents the internal resistance of a fluid to motion, or the fluidity, is _____.

viscosity