Recent questions tagged applications

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GATE2020-ME-2-8
A lossless transmission line with $0.2$ pu reactance per phase uniformly distributed along the length of the line, connecting a generator bus to a load bus, is protected up to $80\%$ of its length by a distance relay placed at the generator bus. The generator terminal voltage ... a solid three phase-to-ground fault on the transmission line is closest to: $1.00$ $3.61$ $5.00$ $6.25$

asked Mar 1 in Others by jothee (2.7k points)

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GATE2020-ME-2-9
Out of the following options, the most relevant information needed to specify the real power $(P)$ at the $PV$ buses in a load flow analysis is solution of economic load dispatch rated power output of the generator rated voltage of the generator base power of the generator

asked Mar 1 in Others by jothee (2.7k points)

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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).

asked Feb 19 in Others by jothee (2.7k points)

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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).

asked Feb 19 in Others by jothee (2.7k points)

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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 $

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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).

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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 _______

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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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)

asked Feb 9, 2019 in Others by Arjun (21.2k points)

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GATE2012-51
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 $0.2$ kg/s. ... $R-134a$ are as follows: The power required for the compressor in kW is $5.94$ $1.83$ $7.9$ $39.5$

asked Mar 20, 2018 in Others by Andrijana3306 (1.5k points)

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GATE2012-50
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 $0.2$ kg/s. ... rate at which heat is extracted, in Kj/s from the refrigerated space is $28.3$ $42.9$ $34.4$ $14.6$

asked Mar 20, 2018 in Others by Andrijana3306 (1.5k points)

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GATE2012-31
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 $67 \%$ $55 \%$ $83 \%$ $71 \%$

asked Mar 20, 2018 in Others by Andrijana3306 (1.5k points)

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GATE2012-7
Steam enters an adiabatic turbine operating at steady state with an enthalpy of $3251.0 \: kJ/kg$ and leaves as a saturated mixture at $15 \:kPa$ with quality (dryness fraction) $0.9$. The enthalpies of the saturated liquid and vapor at $15 \: kPa$ ... Kinetic and potential energy changes are negligible. The power output of the turbine in MW is $6.5$ $8.9$ $9.1$ $27.0$

asked Mar 20, 2018 in Others by Andrijana3306 (1.5k points)

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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).

asked Feb 17, 2018 in Others by Arjun (21.2k points)

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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)

asked Feb 17, 2018 in Others by Arjun (21.2k points)

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GATE2017 ME-2: 42
In the Rankine cycle for a steam power plant, the turbine entry and exit enthalpies are $2803$ kJ/kg and $1800$ kJ/kg, respectively. The enthalpies of water at pump entry and exit are $121$ kJ/kg and $124$ kJ/kg, respectively. The specific steam consumption (in kg/kW.h) of the cycle is _________.

asked Feb 27, 2017 in Others by Arjun (21.2k points)

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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 and heat escapes at ... casing. The mass flow rate of the gas (in kg/s) through the turbine is $6.14$ $7.00$ $7.50$ $8.00$

asked Feb 27, 2017 in Others by Arjun (21.2k points)

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GATE2017 ME-2: 13
Which one of the following statements is TRUE? Both Pelton and Francis turbines are impulse turbines. Francis turbine is a reaction turbine but Kaplan turbine is an impulse turbine. Francis turbine is an axial-flow reaction turbine. Kaplan turbine is an axial-flow reaction turbine.

asked Feb 27, 2017 in Others by Arjun (21.2k points)

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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.

asked Feb 27, 2017 in Others by Arjun (21.2k points)

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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 ________ $K$

asked Feb 27, 2017 in Others by Arjun (21.2k points)

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GATE2016-3-46
In a $3$-stage air compressor, the inlet pressure is $p_1$, discharge pressure is $p_4$.and the intermediate pressures are $p_2$ and $p_3$ ( $p_2 < p_3$). The total pressure ratio of the compressor is $10$ and the pressure ratios of the stages are equal. If $p_1$ = $100$ $kPa$, the value of the pressure $p_3$ (in $kPa$) is __________