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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...

Arjun

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Arjun asked Feb 19, 2017

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GATE2016-3-47
In the vapour compression cycle shown in the figure, the evaporating and condensing temperatures are $260 \: K$ and $310 \: K$, respectively. The compressor takes in liquid-vapour mixture (state $1$) and isentropically compresses it to a dry saturated vapour condition (state ... $1$ and $0$ (in $kJ/kg$) is ____________

In the vapour compression cycle shown in the figure, the evaporating and condensing temperatures are $260 \: K$ and $310 \: K$, respectively. The compressor takes in liqu...

Arjun

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Arjun asked Feb 24, 2017

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ISRO2009-3
The correct sequence of the centrifugal pump components through which the fluid flows is Impeller, Suction pipe, Foot valve and strainer, Delivery pipe Foot valve and strainer, Suction pipe, Impeller, Delivery pipe Impeller, Suction pipe, Delivery pipe, Foot valve and strainer Suction pipe, Delivery pipe, Impeller, Foot valve and strainer

The correct sequence of the centrifugal pump components through which the fluid flows isImpeller, Suction pipe, Foot valve and strainer, Delivery pipeFoot valve and strai...

m2n037

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m2n037 asked Mar 6, 2018

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GATE2018-2-23
An engine operates on the reversible cycle as shown in the figure. The work output from the engine (in (kJ/cycle) is ____ (correct to two decimal places).

An engine operates on the reversible cycle as shown in the figure. The work output from the engine (in (kJ/cycle) is ____ (correct to two decimal places).

Arjun

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Arjun asked Feb 17, 2018

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GATE2019 ME-1: 49
A steam power cycle with regeneration as shown below on the $T-s$ diagram employs a single open feedwater heater for efficiency improvement. The fluid mix with each other in an open feedwater heater. The turbine is isentropic and the input (bleed) to the feedwater ... from the turbine as a percentage of the total mass flow rate at the inlet to the turbine at state $1$ is _______

A steam power cycle with regeneration as shown below on the $T-s$ diagram employs a single open feedwater heater for efficiency improvement. The fluid mix with each other...

Arjun

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Arjun asked Feb 9, 2019

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GATE2017 ME-2: 43
A calorically perfect gas (specific heat at constant pressure $1000 \: J/kg .K$) enters and leaves a gas turbine with the same velocity. The temperatures of the gas at turbine entry and exit are $1100 \: K $and $400 \: K$, respectively. The power produced is $4.6\: MW$ ... turbine casing. The mass flow rate of the gas (in $kg/s$) through the turbine is $6.14$ $7.00$ $7.50$ $8.00$

A calorically perfect gas (specific heat at constant pressure $1000 \: J/kg .K$) enters and leaves a gas turbine with the same velocity. The temperatures of the gas at tu...

Arjun

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Arjun asked Feb 26, 2017

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GATE2017 ME-1: 35
Moist air is treated as an ideal gas mixture of water vapour and dry air (molecular weight of air$= 28.84$ and molecular weight of water $=18$). At a location, the total pressure is $100$ kPa, the temperature is $30^{\circ}$ C and the relative humidity is ... saturation pressure of water at $30^{\circ} C$ is $4246$ Pa, the mass of water vapour per kg of dry air is _________ grams.

Moist air is treated as an ideal gas mixture of water vapour and dry air (molecular weight of air$= 28.84$ and molecular weight of water $=18$). At a location, the total ...

Arjun

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Arjun asked Feb 26, 2017

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GATE ME 2013 | Question: 18
In order to have maximum power from a Pelton turbine, the bucket speed must be equal to the jet speed. equal to half of the jet speed. equal to twice the jet speed. independent of the jet speed.

In order to have maximum power from a Pelton turbine, the bucket speed must beequal to the jet speed.equal to half of the jet speed.equal to twice the jet speed.independe...

piyag476

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piyag476 asked Feb 19, 2017

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GATE2018-2-42
Air is held inside a non-insulated cylinder using a piston (mass $M=25 \: kg$ and area $A=100 \: cm^2$) and stoppers (of negligible area), as shown in the figure. The initial pressure $P_i$ and temperature $T_i$ ... of the air inside the cylinder ($^{\circ}C$) at which the piston will begin to move is ______ (correct to two decimal places).

Air is held inside a non-insulated cylinder using a piston (mass $M=25 \: kg$ and area $A=100 \: cm^2$) and stoppers (of negligible area), as shown in the figure. The ini...

Arjun

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Arjun asked Feb 17, 2018

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GATE2016-3-19
The blade and fluid velocities for an axial turbine are as shown in the figure. The magnitude of absolute velocity at entry is $300$ $m/s$ at an angle of $65^\circ$ to the axial direction, while the magnitude of the absolute velocity at exit is ... downward direction. Given that the axial (horizontal) velocity is the same at entry and exit, the specific work (in $kJ/kg$) is__________

The blade and fluid velocities for an axial turbine are as shown in the figure.The magnitude of absolute velocity at entry is $300$ $m/s$ at an angle of $65^\circ$ to the...

Arjun

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Arjun asked Feb 24, 2017

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GATE2019 ME-1: 12
Consider an ideal vapor compression refrigeration cycle. If the throttling process is replaced by an isentropic expansion process, keeping all the other processes unchanged, which one of the following statements is true for the modified cycle? Coefficient of ... performance is the same as that of the original cycle Refrigerating effect is lower than that of the original cycle

Consider an ideal vapor compression refrigeration cycle. If the throttling process is replaced by an isentropic expansion process, keeping all the other processes unchang...

Arjun

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Arjun asked Feb 9, 2019

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GATE2019 ME-2: 49
An air standard Otto cycle has thermal efficiency of $0.5$ and the mean effective pressure of the cycle is $1000 \: kPa$. For air, assume specific heat ratio $\gamma=1.4$ and specific gas constant $R=0.287 \: kJ/kg \cdot K$. If the pressure and ... $300 \: K$, respectively, then the specific net work output of the cycle is _____ $kJ/kg $ (round off to two decimal places).

An air standard Otto cycle has thermal efficiency of $0.5$ and the mean effective pressure of the cycle is $1000 \: kPa$. For air, assume specific heat ratio $\gamma=1.4$...

Arjun

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Arjun asked Feb 9, 2019

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GATE2019 ME-1: 50
A gas turbine with air as the working fluid has an isentropic efficiency of $0.70$ when operating at a pressure ratio of $3$. Now, the pressure ratio of the turbine is increased to $5$, while maintaining the same inlet conditions. Assume air as a ... the cases, the isentropic efficiency of the turbine at the pressure ratio of $5$ is ___________ (round off to two decimal places)

A gas turbine with air as the working fluid has an isentropic efficiency of $0.70$ when operating at a pressure ratio of $3$. Now, the pressure ratio of the turbine is in...

Arjun

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Arjun asked Feb 9, 2019

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GATE2020-ME-1: 54
For a Kaplan (axial flow) turbine, the outlet blade velocity diagram at a section is shown in the figure. The diameter at this section is $3\:m$.The hub and tip diameters of the blade are $2\:m$ and $4\:m$, respectively. The water volume flow ... rotational speed of the turbine is $300\:rpm$. The blade outlet angle $\beta$ is ________ degrees (round off to one decimal place).

For a Kaplan (axial flow) turbine, the outlet blade velocity diagram at a section is shown in the figure. The diameter at this section is $3\:m$.The hub and tip diam...

go_editor

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go_editor asked Feb 19, 2020

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GATE2019 ME-1: 10
As per common design practice, the three types of hydraulic turbines, in descending order of flow rate, are Kaplan, Francis, Pelton Pelton, Francis, Kaplan Francis, Kaplan, Pelton Pelton, Kaplan, Francis

As per common design practice, the three types of hydraulic turbines, in descending order of flow rate, areKaplan, Francis, PeltonPelton, Francis, KaplanFrancis, Kaplan, ...

Arjun

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Arjun asked Feb 9, 2019

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GATE2020-ME-2: 54
In a steam power plant, superheated steam at $10$ MPa and $500^\circ C$, is expanded isentropically in a turbine until it becomes a saturated vapour. It is then reheated at constant pressure to $500 ^\circ C$. The steam is next expanded isentropically in another turbine until ...

In a steam power plant, superheated steam at $10$ MPa and $500^\circ C$, is expanded isentropically in a turbine until it becomes a saturated vapour. It is then reheated ...

go_editor

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go_editor asked Sep 18, 2020

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GATE2019 ME-1: 31
The rotor of a turbojet engine of an aircraft has a mass $180 \: kg$ and polar moment of inertia $10 \: kg \cdot m^2$ about the rotor axis. The rotor rotates at a constant speed of $1100 \: rad/s$ in the clockwise direction when viewed from the front of the aircraft. The ... the nose goes down $162.9 \: N \cdot m$ and the nose goes up $162.9 \: N \cdot m$ and the nose goes down

The rotor of a turbojet engine of an aircraft has a mass $180 \: kg$ and polar moment of inertia $10 \: kg \cdot m^2$ about the rotor axis. The rotor rotates at a constan...

Arjun

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Arjun asked Feb 9, 2019

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GATE2015-3-47
The torque (in $N$-$m$) exerted on the crank shaft of a two stroke engine can be described as $T = 10000 + 1000 \sin(2θ) − 1200 \cos(2θ)$, where $θ$ is the crank angle as measured from inner dead center position. Assuming the resisting torque to be constant, the power (in $kW$) developed by the engine at $100$ $rpm$ is ________

The torque (in $N$-$m$) exerted on the crank shaft of a two stroke engine can be described as $T = 10000 + 1000 \sin(2θ) − 1200 \cos(2θ)$, where $θ$ is the crank ang...

Arjun

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Arjun asked Feb 24, 2017

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GATE2019 ME-2: 33
The figure shows a heat engine (HE) working between two reservoirs. The amount of heat $(Q_2)$ rejected by the heat engine is drawn by a heat pump (HP). The heat pump receives the entire work output $(W)$ of the heat engine. If temperatures, $T_1 >T_3>T_2$, then the relation between ... $\text{COP}= 1 + \eta$ $\text{COP}= \eta^{-1}$ $\text{COP}= \eta^{-1} -1 $

The figure shows a heat engine (HE) working between two reservoirs. The amount of heat $(Q_2)$ rejected by the heat engine is drawn by a heat pump (HP). The heat pump rec...

Arjun

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Arjun asked Feb 9, 2019

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GATE ME 2012 | Question: 51
A refrigerator operates between $120$ kPa and $800$ kPa in an ideal vapor compression cycle with $R-134a$ as the refrigerant. The refrigerant renters the compressor as saturated vapor and leaves the condenser as saturated liquid. The mass flow rate of the refrigerant is $0.2$ ... $5.94$ $1.83$ $7.9$ $39.5$

A refrigerator operates between $120$ kPa and $800$ kPa in an ideal vapor compression cycle with $R-134a$ as the refrigerant. The refrigerant renters the compressor as sa...

Andrijana3306

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Andrijana3306 asked Mar 19, 2018

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GATE2015-3-52
Which of the following statements are TRUE, when the cavitation parameter $\sigma =0$? the local pressure is reduced to vapor pressure cavitation starts boiling of liquid starts cavitation stops (i), (ii) and (iv) only (ii) and (iii) only (i) and (iii) (i), (ii) and (iii)

Which of the following statements are TRUE, when the cavitation parameter $\sigma =0$?the local pressure is reduced to vapor pressurecavitation startsboiling of liquid st...

Arjun

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Arjun asked Feb 24, 2017

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GATE2018-1-24
For a Pelton wheel with a given water jet velocity, the maximum output power from the Pelton wheel is obtained when the ratio of the bucket speed to the water jet speed is _____ (correct to two decimal places)

For a Pelton wheel with a given water jet velocity, the maximum output power from the Pelton wheel is obtained when the ratio of the bucket speed to the water jet speed i...

Arjun

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Arjun asked Feb 17, 2018

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GATE2016-2-14
Assuming constant temperature condition and air to be an ideal gas, the variation in atmospheric pressure with height calculated from fluid statics is linear exponential quadratic cubic

Assuming constant temperature condition and air to be an ideal gas, the variation in atmospheric pressure with height calculated from fluid statics islinearexponentialqua...

Arjun

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Arjun asked Feb 24, 2017

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GATE2016-1-46
An ideal gas undergoes a reversible process in which the pressure varies linearly with volume. The conditions at the start (subscript $1$) and at the end (subscript $2$) of the process with usual notation are: $p_1 = 100 \: kPa$, $V_1 = 0.2 \: m^3$ ... $R=0.275\:kJ/kg-K$. The magnitude of the work required for the process (in $kJ$) is ________

An ideal gas undergoes a reversible process in which the pressure varies linearly with volume. The conditions at the start (subscript $1$) and at the end (subscript $2$) ...

Arjun

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Arjun asked Feb 24, 2017

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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...

Arjun

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Arjun asked Feb 19, 2017

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GATE ME 2012 | Question: 31
A room contains $35$ kg of dry air and $0.5$ kg of water vapor. The total pressure and temperature of air in the room are $100$ kPa and $25^{\circ}$C respectively. Given that the saturation pressure for water at $25^{\circ}$ C is $3.17$ kPa, the relative humidity of the air in the room is $67 \%$ $55 \%$ $83 \%$ $71 \%$

A room contains $35$ kg of dry air and $0.5$ kg of water vapor. The total pressure and temperature of air in the room are $100$ kPa and $25^{\circ}$C respectively. Given ...

Andrijana3306

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Andrijana3306 asked Mar 19, 2018

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GATE2020-ME-1: 24
The compressor of a gas turbine plant, operating on an ideal intercooled Brayton cycle, accomplishes an overall compression ratio of $6$ in a two-stage compression process. Intercooling is used to cool the air coming out from the first stage to the ... gas are constant, the intercooling pressure for minimum compressor work is __________ $kPa$ (rounded off to $2$ decimal places).

The compressor of a gas turbine plant, operating on an ideal intercooled Brayton cycle, accomplishes an overall compression ratio of $6$ in a two-stage compression proces...

go_editor

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go_editor asked Feb 19, 2020

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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...

Arjun

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Arjun asked Feb 19, 2017

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GATE2020-ME-2: 6
A circular disk of radius $r$ is confined to roll without slipping at $P$ and $Q$ as shown in the figure. If the plates have velocities as shown, the magnitude of angular velocity of the disk is $\dfrac{V}{r} \\$ $\dfrac{V}{2r} \\$ $\dfrac{2V}{3r} \\$ $\dfrac{3V}{2r} $

A circular disk of radius $r$ is confined to roll without slipping at $P$ and $Q$ as shown in the figure.If the plates have velocities as shown, the magnitude of angular ...

go_editor

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go_editor asked Sep 18, 2020

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GATE2015-3-45
A bullet spins as the shot is fired from a gun. For this purpose, two helical slots as shown in the figure are cut in the barrel. Projections $A$ and $B$ on the bullet engage in each of the slots. Helical slots are such that one turn of helix is completed over a ... $m$. If velocity of bullet when it exits the barrel is $20$ $m/s$, its spinning speed in $rad/s$ is ________

A bullet spins as the shot is fired from a gun. For this purpose, two helical slots as shown in the figure are cut in the barrel. Projections $A$ and $B$ on the bullet en...

Arjun

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Arjun asked Feb 24, 2017

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GATE2020-ME-2: 17
For an air-standard Diesel cycle, heat addition is at constant volume and heat rejection is at constant pressure heat addition is at constant pressure and heat rejection is at constant pressure heat addition is at constant pressure and heat rejection is at constant volume heat addition is at constant volume and heat rejection is at constant volume

For an air-standard Diesel cycle,heat addition is at constant volume and heat rejection is at constant pressureheat addition is at constant pressure and heat rejection is...

go_editor

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go_editor asked Sep 18, 2020

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GATE2018-1-23
An ideal gas undergoes a process from state $1 \: (T_1 = 300\: K, \: p_1 = 100 \: kPa)$ to state $2 \: (T_2 = 600 \; K, \: p_2 = 500 \: kPa)$. The specific heats of the ideal gas are: $C_p = 1 \: kJ/kg-K$ and $C_v = 0.7 \: kJ/kg-K$. The change in specific entropy of the ideal gas from state $1$ to state $2$ (in $kJ/kg-K$) is ______ (correct to two decimal places).

An ideal gas undergoes a process from state $1 \: (T_1 = 300\: K, \: p_1 = 100 \: kPa)$ to state $2 \: (T_2 = 600 \; K, \: p_2 = 500 \: kPa)$. The specific heats of the...

Arjun

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Arjun asked Feb 17, 2018

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GATE2017 ME-1: 34
The pressure ratio across a gas turbine (for air, specific heat at constant pressure, $c_{p}=1040 J/kg.K$ and ratio of specific heats, $\gamma=1.4$) is $10$. If the inlet temperature to the turbine is $1200$ K and the isentropic efficiency is $0.9$, the gas temperature at turbine exit is ________ $K$

The pressure ratio across a gas turbine (for air, specific heat at constant pressure, $c_{p}=1040 J/kg.K$ and ratio of specific heats, $\gamma=1.4$) is $10$. If the inlet...

Arjun

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Arjun asked Feb 26, 2017

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GATE2018-2-45
A test is conducted on a one-fifth scale model of a Francis turbine under a head of $2 \: m$ and volumetric flow rate of $1 \: m^3/s$ at $450 \: rpm$. Take the water density and the acceleration due to gravity as $10^3 \: kg/m^3$ ... prototype turbines. The power (in MW) of a full sized turbine while working under a head of $30 \: m$ is _______ (correct to two decimal places)

A test is conducted on a one-fifth scale model of a Francis turbine under a head of $2 \: m$ and volumetric flow rate of $1 \: m^3/s$ at $450 \: rpm$. Take the water dens...

Arjun

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Arjun asked Feb 17, 2018

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GATE ME 2012 | Question: 50
A refrigerator operates between $120$ kPa and $800$ kPa in an ideal vapor compression cycle with $R-134a$ ... at which heat is extracted, in Kj/s from the refrigerated space is $28.3$ $42.9$ $34.4$ $14.6$

A refrigerator operates between $120$ kPa and $800$ kPa in an ideal vapor compression cycle with $R-134a$ as the refrigerant. The refrigerant renters the compressor as sa...

Andrijana3306

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Andrijana3306 asked Mar 19, 2018

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GATE2018-2-55
A vehicle powered by a spark ignition engine follows air standard Otto cycle ($\gamma =1.4$). The engine generates $70$ kW while consuming $10.3$ kg/hr of fuel. The calorific value of the fuel is $44,000 \: kJ/kg$. The compression ratio is _________ (correct to two decimal places.

A vehicle powered by a spark ignition engine follows air standard Otto cycle ($\gamma =1.4$). The engine generates $70$ kW while consuming $10.3$ kg/hr of fuel. The calor...

Arjun

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Arjun asked Feb 17, 2018

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GATE2016-1-19
The INCORRECT statement about regeneration in vapor power cycle is that it increases the irreversibility by adding the liquid with higher energy content to the steam generator heat is exchanged between the expanding fluid in the turbine and the compressed ... the principle is similar to the principle of Stirling gas cycle it is practically implemented by providing feed water heaters

The INCORRECT statement about regeneration in vapor power cycle is thatit increases the irreversibility by adding the liquid with higher energy content to the steam gener...

Arjun

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Arjun asked Feb 24, 2017

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GATE2020-ME-2: 48
Consider a flow through a nozzle, as shown in the figure below. The air flow is steady, incompressible and inviscid. The density of air is $1.23 \: kg/m^3$. The pressure difference, $(p_1-p_{\text{atm}})$ is _________ kPa (round off to $2$ decimal places)

Consider a flow through a nozzle, as shown in the figure below.The air flow is steady, incompressible and inviscid. The density of air is $1.23 \: kg/m^3$. The pressure d...

go_editor

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go_editor asked Sep 18, 2020

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GATE2018-1-46
An engine working on air standard Otto cycle is supplied with air at $0.1 MPa$ and $35^{\circ} \: C$. The compression ratio is $8$. The heat supplied is $500 \: kJ/kg \: K$. The maximum temperature (in $K$) of the cycle is _______ (correct to one decimal place)

An engine working on air standard Otto cycle is supplied with air at $0.1 MPa$ and $35^{\circ} \: C$. The compression ratio is $8$. The heat supplied is $500 \: kJ/kg \: ...

Arjun

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Arjun asked Feb 17, 2018

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GATE Mechanical 2014 Set 2 | Question: 49
A heat pump with refrigerant $R22$ is used for space heating between temperature limits of $−20^\circ C$ and $25^ \circ C$. The heat required is $200 MJ/h$ ... $kJ/kg$) of the refrigerant at isentropic compressor discharge is _______

A heat pump with refrigerant $R22$ is used for space heating between temperature limits of $−20^\circ C$ and $25^ \circ C$. The heat required is $200 MJ/h$. Assume spec...

Arjun

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Arjun asked Feb 19, 2017