# Recent questions tagged vapour-and-gas-power-cycles

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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 heater from ... bled from the turbine as a percentage of the total mass flow rate at the inlet to the turbine at state $1$ is _______
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).
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 $55\%$. ... the saturation pressure of water at $30^{\circ} C$ is $4246$ Pa, the mass of water vapour per kg of dry air is _________ grams.
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 $2$). ... is $1054 \: kJ/kg$. The difference between the enthalpies at state points $1$ and $0$ (in $kJ/kg$) is ____________
The partial pressure of the water vapour in a moist air sample of relative humidity $70\%$ is $1.6 \: kPa$,the total pressure being $101.35 \: kPa$.moist air may be treated as an ideal gas mixture of water vapour and dry air.the relation between saturation temperature ($T_s$ ... $p_o=101.325 \: kPa$. The dry bulb temperature of the moist air sample (in $_{}^{\circ}\textrm{C}$) is
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
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: $p_1 = 100 \: kPa$, $V_1 = 0.2 \: m^3$ and $p_2=200 \: kPa$ ... $R=0.275\:kJ/kg-K$. The magnitude of the work required for the process (in $kJ$) is ________
In a steam power plant operating on an ideal Rankine cycle, superheated steam enters the turbine at $3 \: MPa$ and $350^ \circ C$. The condenser pressure is $75$ $kPa$. The thermal efficiency of the cycle is ________ percent. Given data: For saturated liquid, at $P=75 \:kPa$, $h_f=384.39 \:kJ/kg$ ... $P = 3 \: MPa$ and $T=350^\circ C$ (superheated steam), $h=3115.3 \: kJ/kg$, $s=6.7428 \: kJ/kg-K$
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)
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 ____________
In a simple Brayton cycle, the pressure ratio is $8$ and temperatures at the entrance of compressor and turbine are $300$ $K$ and $1400$ $K$, respectively. Both compressor and gas turbine have isentropic efficiencies equal to $0.8$. For the gas, assume a constant value of $c_p$ (specific ... . The power required by the compressor in $kW$/$kg$ of gas flow rate is $194.7$ $243.4$ $304.3$ $378.5$
In a simple Brayton cycle, the pressure ratio is $8$ and temperatures at the entrance of compressor and turbine are $300$ $K$ and $1400$ $K$, respectively. Both compressor and gas turbine have isentropic efficiencies equal to $0.8$ ... kinetic and potential energies. The thermal efficiency of the cycle in percentage (%) is $24.8$ $38.6$ $44.8$ $53.1$