Recent questions tagged fluid-mechanics-and-thermal-science / GO Mechanical

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GATE2015-2-13
Which of the following statements regarding a Rankine cycle with reheating are TRUE? increase in average temperature of heat addition reduction in thermal efficiency drier steam at the turbine exit only $(i)$ and $(ii)$ are correct only $(ii)$ and $(iii)$ are correct only $(i)$ and $(iii)$ are correct $(i)$, $(ii)$ and $(iii)$ are correct

Which of the following statements regarding a Rankine cycle with reheating are TRUE?increase in average temperature of heat additionreduction in thermal efficiencydrier s...

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GATE2015-2-12
If the fluid velocity for a potential flow is given by $V(x,y)=u(x,y)i+v(x,y)j$ with usual notations, then the slope of the potential line at $(x,y)$ is $\dfrac{v}{u} \\$ $-\dfrac{u}{v} \\$ $\dfrac{u^2}{v^2} \\$ $\dfrac{u}{v}$

If the fluid velocity for a potential flow is given by $V(x,y)=u(x,y)i+v(x,y)j$ with usual notations, then the slope of the potential line at $(x,y)$ is$\dfrac{v}{u} \\$$...

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GATE2015-1-55
Steam enters a well insulated turbine and expands isentropically throughout. At an intermediate pressure, $20$ percent of the mass is extracted for process heating and the remaining steam expands isentropically to $9 \: kPa$ ... If the flow rate of steam entering the turbine is $100$ $kg/s$, then the work output (in $MW$) is _________

Steam enters a well insulated turbine and expands isentropically throughout. At an intermediate pressure, $20$ percent of the mass is extracted for process heating and th...

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GATE2015-1-54
A well insulated rigid container of volume $1 \: m^3$ contains $1.0 \: kg$ of an ideal gas $[C_p = 1000 \: J/(kg\cdot K)$ and $C_v=800 J/(kg \cdot K)]$ at a pressure of $105 \: Pa$. A stirrer is rotated at constant rpm in the container for $1000$ rotations and the applied torque is $100 \: N-m$. The final temperature of the gas (in $K$) is $500.0$ $773.0$ $785.4$ $1285.4$

A well insulated rigid container of volume $1 \: m^3$ contains $1.0 \: kg$ of an ideal gas $[C_p = 1000 \: J/(kg\cdot K)$ and $C_v=800 J/(kg \cdot K)]$ at a pressure of ...

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GATE2015-1-53
Water $(\rho = 1000 \: kg/m^3)$ flows through a venturimeter with inlet diameter $80 \: mm$ and throat diameter $40 \: mm$. The inlet and throat gauge pressures are measured to be $400 \: kPa$ and $130 \: kPa$ respectively. Assuming the venturimeter to be horizontal and neglecting friction, the inlet velocity (in $m/s$) is _______

Water $(\rho = 1000 \: kg/m^3)$ flows through a venturimeter with inlet diameter $80 \: mm$ and throat diameter $40 \: mm$. The inlet and throat gauge pressures are measu...

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GATE2015-1-50
A $10$ $mm$ diameter electrical conductor is covered by an insulation of $2\:mm$ thickness. The conductivity of the insulation is $0.08$ $W/m-K$ and the convection coefficient at the insulation surface is $10$ $W/m^2-K$. Addition of ... heat loss continuously increase heat loss to a maximum and then decrease heat loss decrease heat loss to a minimum and then increase heat loss

A $10$ $mm$ diameter electrical conductor is covered by an insulation of $2\:mm$ thickness. The conductivity of the insulation is $0.08$ $W/m-K$ and the convection coeffi...

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GATE2015-1-48
Match the following pairs: \begin{array}{|l|l|l|l|} \hline &\textbf{Equation} && \textbf{Physical Interpretation} \\ \hline P. & \nabla \times \overrightarrow{V}=0 & I. & \text{ Incompressible continuity equation} \\ \hline Q. & \nabla \bullet \overrightarrow{V}=0 & II. ... $P-IV, Q-III, R-I, S-II$ $P-III, Q-I, R-IV, S-II$ $P-III, Q-I, R-II, S-IV$

Match the following pairs:\begin{array}{|l|l|l|l|} \hline &\textbf{Equation} && \textbf{Physical Interpretation} \\ \hline P. & \nabla \times \overrightarrow{V}=0 & I. & ...

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GATE2015-1-47
For flow through a pipe of radius $R$, the velocity and temperature distribution are as follows: $u(r,x)=C_1,$, and $T(r,x)=C_2[1- \left (\dfrac{r}{R} \right )^3]$ where $C_1$ and $C_2$ ... mean velocity of flow. The value of $T_m$ is $\dfrac{0.5C_2}{U_m} \\$ $0.5C_2 \\$ $0.6C_2 \\$ $\dfrac{0.6C_2}{U_m}$

For flow through a pipe of radius $R$, the velocity and temperature distribution are as follows:$u(r,x)=C_1,$, and $T(r,x)=C_2[1- \left (\dfrac{r}{R} \right )^3]$ where $...

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GATE2015-1-13
A wheel of radius $r$ rolls without slipping on a horizontal surface shown below. If the velocity of point $P$ is $10$ $m/s$ in the horizontal direction, the magnitude of velocity of point $Q$ (in $m/s$) is ______

A wheel of radius $r$ rolls without slipping on a horizontal surface shown below. If the velocity of point $P$ is $10$ $m/s$ in the horizontal direction, the magnitude of...

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GATE2015-1-18
A swimmer can swim $10$ $km$ in $2$ hours when swimming along the flow of a river. While swimming against the flow, she takes $5$ hours for the same distance. Her speed in still water (in $km/h$) is _____

A swimmer can swim $10$ $km$ in $2$ hours when swimming along the flow of a river. While swimming against the flow, she takes $5$ hours for the same distance. Her speed i...

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GATE2015-1-12
A stream of moist air (mass flow rate $= 10.1 \: kg/s$) with humidity ratio of $0.01 \: \dfrac{kg}{\text{kg dry air}}$ mixes with a second stream of superheated water vapour flowing at $0.1 \: \text{kg/s}$. Assuming proper and uniform mixing with no condensation, the humidity ratio of the final stream $\big($in $\dfrac{kg}{\text{kg dry air}} \big )$ is _____________

A stream of moist air (mass flow rate $= 10.1 \: kg/s$) with humidity ratio of $0.01 \: \dfrac{kg}{\text{kg dry air}}$ mixes with a second stream of superheated water va...

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GATE2015-1-11
Air enters a diesel engine with a density of $1.0$ $kg$/$m^3$. The compression ratio is $21$. At steady state, the air intake is $30 × 10^{-3}$ $kg/s$ and the net work output is $15$ $kW$. The mean effective pressure (in $kPa$) is ____________

Air enters a diesel engine with a density of $1.0$ $kg$/$m^3$. The compression ratio is $21$. At steady state, the air intake is $30 × 10^{-3}$ $kg/s$ and the net work o...

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GATE2015-1-10
A Carnot engine ($CE_1$) works between two temperature reservoirs $A$ and $B$, where $T_A$ = $900$ $K$ and $T_B$ = $500$ $K$. A second Carnot engine ($CE_2$) works between temperature reservoirs $B$ and $C$, where $T_C$ = $300$ $K$ ... $CE_1$ from reservoir $A$ is $150$ $MJ$, the net heat rejected to reservoir $C$ by $CE_2$ (in $MJ$) is ______________

A Carnot engine ($CE_1$) works between two temperature reservoirs $A$ and $B$, where $T_A$ = $900$ $K$ and $T_B$ = $500$ $K$. A second Carnot engine ($CE_2$) works betwee...

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GATE2015-1-9
For an ideal gas with constant values of specific heats, for calculation of the specific enthalpy, it is sufficient to know only the temperature both temperature and pressure are required to be known both temperature and volume are required to be known both temperature and mass are required to be known

For an ideal gas with constant values of specific heats, for calculation of the specific enthalpy,it is sufficient to know only the temperatureboth temperature and pressu...

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GATE2015-1-8
For flow of viscous fluid over a flat plate, if the fluid temperature is the same as the plate temperature, the thermal boundary layer is thinner than the velocity boundary layer thicker than the velocity boundary layer of the same thickness as the velocity boundary layer not formed at all

For flow of viscous fluid over a flat plate, if the fluid temperature is the same as the plate temperature, the thermal boundary layer isthinner than the velocity boundar...

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GATE2015-1-6
Consider fully developed flow in a circular pipe with negligible entrance length effects. Assuming the mass flow rate, density and friction factor to be constant, if the length of the pipe is doubled and the diameter is halved, the head loss due to friction will increase by a factor of $4$ $16$ $32$ $64$

Consider fully developed flow in a circular pipe with negligible entrance length effects. Assuming the mass flow rate, density and friction factor to be constant, if the ...

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GATE Mechanical 2014 Set 4 | Question: 49
In a compression ignition engine, the inlet air pressure is $1$ bar and the pressure at the end of isentropic compression is $32.42$ bar. The expansion ratio is $8$. Assuming ratio of specific heats $(γ)$ as $1.4$, the air standard efficiency (in percent) is _______

In a compression ignition engine, the inlet air pressure is $1$ bar and the pressure at the end of isentropic compression is $32.42$ bar. The expansion ratio is $8$. Assu...

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GATE Mechanical 2014 Set 4 | Question: 48
Two infinite parallel plates are placed at a certain distance apart. An infinite radiation shield is inserted between the plates without touching any of them to reduce heat exchange between the plates. Assume that the emissivities of plates and radiation shield are equal ... exchange between the plates with and without the shield is $1/2$ $1/3$ $1/4$ $1/8$

Two infinite parallel plates are placed at a certain distance apart. An infinite radiation shield is inserted between the plates without touching any of them to reduce he...

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GATE Mechanical 2014 Set 4 | Question: 47
Steam with specific enthalpy $(h)$ $3214$ $kJ/kg$ enters an adiabatic turbine operating at steady state with a flow rate $10$ $kg/s$. As it expands, at a point where h is $2920$ $kJ/kg$, $1.5$ $kg/s$ is extracted for heating ... = $2374$ $kJ/kg$. Neglecting changes in kinetic and potential energies, the net power output (in $kW$) of the turbine is _______

Steam with specific enthalpy $(h)$ $3214$ $kJ/kg$ enters an adiabatic turbine operating at steady state with a flow rate $10$ $kg/s$. As it expands, at a point where h is...

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GATE Mechanical 2014 Set 4 | Question: 46
Two identical metal blocks L and M (specific heat = $0.4$ $kJ/kg.K$), each having a mass of $5$ $kg$, are initially at $313$ $K$. A reversible refrigerator extracts heat from block L and rejects heat to block M until the temperature of block L reaches $293$ $K$. The final temperature (in $K$) of block M is _______

Two identical metal blocks L and M (specific heat = $0.4$ $kJ/kg.K$), each having a mass of $5$ $kg$, are initially at $313$ $K$. A reversible refrigerator extracts heat ...

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GATE Mechanical 2014 Set 4 | Question: 45
Water flows through a tube of diameter $25$ $mm$ at an average velocity of $1.0$ $m/s$. The properties of water are $\rho$=$1000$ $kg/m^3$, $\mu$=$7.25 ×10^{−4}$ $N.s/m^2$, $k$=$0.625$ $W/m.K$, $P_r$ = $4.85$. Using $N_\mu =0.023R_e^{0.8}P_r^{0.4}$ , the convective heat transfer coefficient (in $W/m^2.K$) is _______

Water flows through a tube of diameter $25$ $mm$ at an average velocity of $1.0$ $m/s$. The properties of water are $\rho$=$1000$ $kg/m^3$, $\mu$=$7.25 ×10^{−4}$ $N.s/...

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GATE Mechanical 2014 Set 4 | Question: 42
A plane wall has a thermal conductivity of $1.15$ $W/m.K$. If the inner surface is at $1100^{\circ} C$ and the outer surface is at $350^{\circ} C$, then the design thickness (in meter) of the wall to maintain a steady heat flux of $2500$ $W/m^2$ should be _______

A plane wall has a thermal conductivity of $1.15$ $W/m.K$. If the inner surface is at $1100^{\circ} C$ and the outer surface is at $350^{\circ} C$, then the design thickn...

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GATE Mechanical 2014 Set 4 | Question: 41
A closed system contains $10$ $kg$ of saturated liquid ammonia at $10^{\circ}$ $C$. Heat addition required to convert the entire liquid into saturated vapour at a constant pressure is $16.2$ $MJ$. If the entropy of the saturated liquid is $0.88$ $kJ/kg.K$, the entropy (in $kJ/kg.K$) of saturated vapour is _______

A closed system contains $10$ $kg$ of saturated liquid ammonia at $10^{\circ}$ $C$. Heat addition required to convert the entire liquid into saturated vapour at a constan...

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GATE Mechanical 2014 Set 4 | Question: 24
Match the heat treatment processes (Group A) and their associated effects on properties (Group B) of medium carbon steel ... $P-III, Q-II, R-IV, S-I$ $P-II, Q-III, R-I, S-IV$

Match the heat treatment processes (Group A) and their associated effects on properties (Group B) of medium carbon steel$\begin{array}{|l|l|} \hline \textbf{Group A} & \t...

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GATE Mechanical 2014 Set 4 | Question: 16
Kaplan water turbine is commonly used when the flow through its runner is axial and the head available is more than $100$ $m$ axial and the head available is less than $10$ $m$ radial and the head available is more than $100$ $m$ mixed and the head available is about $50$ $m$

Kaplan water turbine is commonly used when the flow through its runner isaxial and the head available is more than $100$ $m$axial and the head available is less than $10$...

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GATE Mechanical 2014 Set 4 | Question: 15
Match Group A with Group B: ... $P-4, Q-3, R-1, S-2$ $P-3, Q-2, R-1, S-4$ $P-2, Q-1, R-3, S-4$

Match Group A with Group B:$\begin{array}{|l|l|} \hline \textbf{Group A} & \textbf{Group B} \\ \hline \text{P: Biot number} & \text{1: Ratio of buoyancy to viscous force}...

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GATE Mechanical 2014 Set 4 | Question: 14
A flow field which has only convective acceleration is a steady uniform flow an unsteady uniform flow a steady non-uniform flow an unsteady non-uniform flow

A flow field which has only convective acceleration isa steady uniform flowan unsteady uniform flowa steady non-uniform flowan unsteady non-uniform flow

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GATE Mechanical 2014 Set 4 | Question: 13
A reversed Carnot cycle refrigerator maintains a temperature of −$5^{\circ}$ $C$. The ambient air temperature is $35^{\circ}$ $C$. The heat gained by the refrigerator at a continuous rate is $2.5$ kJ/s. The power (in watt) required to pump this heat out continuously is _______

A reversed Carnot cycle refrigerator maintains a temperature of −$5^{\circ}$ $C$. The ambient air temperature is $35^{\circ}$ $C$. The heat gained by the refrigerator a...

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GATE Mechanical 2014 Set 4 | Question: 12
As the temperature increases, the thermal conductivity of a gas increases decreases remains constant increases up to a certain temperature and then decreases

As the temperature increases, the thermal conductivity of a gas increasesdecreasesremains constantincreases up to a certain temperature and then decreases

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GATE Mechanical 2014 Set 3 | Question: 50
Consider the given project network, where numbers along various activities represent the normal time. The free float on activity $4$-$6$ and the project duration, respectively, are $2$, $13$ $0$, $13$ $-2$, $13$ $2$, $12$

Consider the given project network, where numbers along various activities represent the normal time. The free float on activity $4$-$6$ and the project duration, respect...

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GATE Mechanical 2014 Set 3 | Question: 49
A diesel engine has a compression ratio of $17$ and cut-off takes place at $10\%$ of the stroke.Assuming ratio of specific heats $(\gamma)$ as $1.4$, the air-standard efficiency (in percent) is _______

A diesel engine has a compression ratio of $17$ and cut-off takes place at $10\%$ of the stroke.Assuming ratio of specific heats $(\gamma)$ as $1.4$, the air-standard eff...

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GATE Mechanical 2014 Set 3 | Question: 48
A double-pipe counter-flow heat exchanger transfers heat between two water streams. Tube side water at $19$ liter/s is heated from $10^{\circ} \: C$ to $38^{\circ} \: C$. Shell side water at $25$ $litre/s$ is entering at $46^{\circ} \: C$. Assume ... density is $1000 \: kg/m^3$ and specific heat is $4186 \: J/kg.K$. The LM TD (in $^{\circ}C$) is _______

A double-pipe counter-flow heat exchanger transfers heat between two water streams. Tube side water at $19$ liter/s is heated from $10^{\circ} \: C$ to $38^{\circ} \: C$....

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GATE Mechanical 2014 Set 3 | Question: 47
A solid sphere of radius $r_1 = 20$ $mm$ is placed concentrically inside a hollow sphere of radius $r_2 = 30$ $mm$ as shown in the figure. The view factor $F_{21}$ for radiation heat transfer is $\dfrac{2}{3} \\$ $\dfrac{4}{9} \\$ $\dfrac{8}{27} \\$ $\dfrac{9}{4}$

A solid sphere of radius $r_1 = 20$ $mm$ is placed concentrically inside a hollow sphere of radius $r_2 = 30$ $mm$ as shown in the figure.The view factor $F_{21}$ for ra...

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GATE Mechanical 2014 Set 3 | Question: 46
At the inlet of an axial impulse turbine rotor, the blade linear speed is $25 \: m/s$, the magnitude of absolute velocity is $100 \: m/s$ and the angle between them is $25^{\circ}$. The relative velocity and the axial component ... blade inlet and outlet velocity triangles are shown in the figure. Assuming no losses, the specific work (in $J/kg$) is _______

At the inlet of an axial impulse turbine rotor, the blade linear speed is $25 \: m/s$, the magnitude of absolute velocity is $100 \: m/s$ and the angle between them is $2...

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GATE Mechanical 2014 Set 3 | Question: 45
A fluid of dynamic viscosity $2 × 10^{−5}$ $kg/m.s$ and density $1$ $kg/m^3$ flows with an average velocity of $1$ $m/s$ through a long duct of rectangular ($25$ $mm$ × $15$ $mm$) cross-section. Assuming laminar flow, the pressure drop (in $Pa$) in the fully developed region per meter length of the duct is _______

A fluid of dynamic viscosity $2 × 10^{−5}$ $kg/m.s$ and density $1$ $kg/m^3$ flows with an average velocity of $1$ $m/s$ through a long duct of rectangular ($25$ $mm$ ...

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GATE Mechanical 2014 Set 3 | Question: 44
Heat transfer through a composite wall is shown in figure. Both the sections of the wall have equal thickness $(l)$. The conductivity of one section is $k$ and that of the other is $2k$. The left face of the wall is at $600$ $K$ and the right face is at $300$ $K$. The interface temperature $T_i$ (in $K$) of the composite wall is _______

Heat transfer through a composite wall is shown in figure. Both the sections of the wall have equal thickness $(l)$. The conductivity of one section is $k$ and that of th...

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GATE Mechanical 2014 Set 3 | Question: 43
A siphon is used to drain water from a large tank as shown in the figure below. Assume that the level of water is maintained constant. Ignore frictional effect due to viscosity and losses at entry,and exit. At the exit of the siphon, the velocity of water is $\sqrt{2g(Z_Q-Z_R)} \\$ $\sqrt{2g(Z_P-Z_R)} \\$ $\sqrt{2g(Z_O-Z_R)} \\$ $\sqrt{2gZ_Q}$

A siphon is used to drain water from a large tank as shown in the figure below. Assume that the level of water is maintained constant. Ignore frictional effect due to vis...

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GATE Mechanical 2014 Set 3 | Question: 42
An amount of $100 \: kW$ of heat is transferred through a wall in steady state. One side of the wall is maintained at $127^{\circ} \: C$ and the other side at $27^{\circ} \: C$. The entropy generated (in $W/K$) due to the heat transfer through the wall is _______

An amount of $100 \: kW$ of heat is transferred through a wall in steady state. One side of the wall is maintained at $127^{\circ} \: C$ and the other side at $27^{\circ}...

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GATE Mechanical 2014 Set 3 | Question: 41
A certain amount of an ideal gas is initially at a pressure $p_1$ and temperature $T_1$. First, it undergoes a constant pressure process $1$-$2$ such that $T_2$ = $3T_1$/$4$. Then, it undergoes a constant volume process $2$-$3$ such that $T_3$ = $T_1$/$2$. The ratio of the final volume to the initial volume of the ideal gas is $0.25$ $0.75$ $1.0$ $1.5$

A certain amount of an ideal gas is initially at a pressure $p_1$ and temperature $T_1$. First, it undergoes a constant pressure process $1$-$2$ such that $T_2$ = $3T_1$/...

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GATE Mechanical 2014 Set 3 | Question: 17
A sample of moist air at a total pressure of $85$ $kPa$ has a dry bulb temperature of $30^oC$ (saturation vapour pressure of water = $4.24$ $kPa$). If the air sample has a relative humidity of $65$%, the absolute humidity (in gram) of water vapour per $kg$ of dry air is _______

A sample of moist air at a total pressure of $85$ $kPa$ has a dry bulb temperature of $30^oC$ (saturation vapour pressure of water = $4.24$ $kPa$). If the air sample has ...

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