Power Cycles

A thermal power plant is running with no reheat or regeneration. The specific enthalpy and specific entropy of steam at the turbine inlet are $3344 \mathrm{~kJ} \mathrm{~kg}^{-1}$ and $6.5 \mathrm{~kJ} \mathrm{~kg}^{-1}...

The thermal efficiency of an ideal air-standard Otto cycle is 0.5 . The value of specific heat ratio of air is 1.4. The compression ratio of the cycle is _________ (rounded off to 1 decimal place).

Which one of the following statements regarding a Rankine cycle is FALSE?

An engine running on an air standard Otto cycle has a displacement volume 250 cm 3 and a clearance volume 35.7 cm 3 . The pressure and temperature at the beginning of the compression process are 100 kPa and 300 K, respec...

In a steam power plant based on Rankine cycle, steam is initially expanded in a high-pressure turbine. The steam is then reheated in a reheater and finally expanded in a low-pressure turbine. The expansion work in the hi...

In the Rankine cycle for a system 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 $$...

In a steam power plant operating on an ideal Rankine cycle, super-heated steam enters the turbine at $$3$$ $$MPa$$ and $${350^ \circ }C.$$ The condenser pressure is $$75$$ $$kPa.$$ Thermal efficiency of the cycle is ____...

The INCORRECT statement about regeneration in vapor power cycle is that

Which of the following statements regarding a Rankine cycle with reheating are TRUE ? (i) increase in average temperature of heat addition (ii) reduction in thermal efficiency (iii) drier steam at the turbine exit

In a Rankine cycle, the enthalpies at turbine entry and outlet are $$3159$$ $$kJ/kg$$ and $$2187$$ $$kJ/kg$$ respectively. If the specific pump work is $$2$$ $$kJ/kg,$$ the specific steam consumption (in $$kg/k$$$$W$$-$$...

Steam at a velocity of $$10$$ $$m/s$$ enters the impulse turbine stage with symmetrical blading having blade angle $${30^ \circ }.$$ The enthalpy drop in the stage is $$100kJ.$$ The nozzle angle is $${20^ \circ }.$$ The...

The values of enthalpy of steam at the inlet and outlet of a steam turbine in a Rankine cycle are $$2800$$ $$kJ/kg$$ and $$1800$$ $$kJ/kg$$ respectively. Neglecting pump work, the specific steam consumption in $$kg/kW$$-...

Which combination of the following statements is correct? The incorporation of re-heater in a steam power plant. $$P:$$ always increases the thermal efficiency of the plant. $$Q:$$ always increases the dryness function o...

Assertion (A): Condenser is an essential equipment in a steam power plant. Reason(R): For the same mass flow rate and the same pressure rise, a water pump requires substantially less power than a steam compressor.

Determine the correctness or otherwise of the following Assertion $$(a)$$ and the Reason$$(r).$$ Assertion(A): In a power plant working on a Rankine cycle, the regenerative feed water heating improves the efficiency of t...

Considering the variation of static pressure and absolute velocity in an impulse stream turbine, across one row of moving blades

In a Rankine cycle, regeneration results in higher efficiency because

The efficiency of superheat Rankine cycle is higher than that of simple Rankine cycle because

The Rateau turbine belongs to the category of

Which of the following is a pressure compounded turbine?

A simple impulse turbine expands steam frictionlessly from $$12$$ bar, $${250^0}C$$ with an enthalpy of $$2935$$ $$kJ/kg$$ to an enthalpy of $$2584$$ $$kJ/kg$$ at $$0.1$$ bar. Assuming that the nozzle makes an angle of $...

A Curtis stage, Rateau stage and a $$50$$% reaction stage in a steam turbine are examples of

If $$\,\,{V_N}\,\,$$ and $$\alpha $$ are the nozzle exit velocity and nozzle angle in an impulse turbine, the optimum blade velocity is given by

The isentropic heat drop in the nozzle of an impulse steam turbine with a nozzle efficiency $$0.9,$$ blade velocity ratio $$0.5,$$ and mean blade velocity $$150$$ $$m/s$$ in $$kJ/kg$$ is

Consider an actual regenerative Rankine cycle with one open feed water heater. For each $$kg$$ steam entering the turbine, if $$m$$ $$kg$$ steam with a specific enthalpy of $${h_1}$$ is bled from the turbine, and the spe...

Which among the following is the boiler mounting?

A steam plant has the boiler efficiency of $$92\% $$, turbine efficiency (mechanical) of $$94\% $$, generator efficiency of $$92\% $$ and cycle efficiency of $$44\% $$. If $$6\% $$ of the generated power is used to run t...

For two cycles coupled in series, the topping cycle has an efficiency of $$30\% $$ and the bottoming cycle has an efficiency of $$20\% $$. The overall combined cycle efficiency is

Consider a Rankine cycle with superheat. If the maximum pressure in the cycle is increased without changing the maximum temperature and the minimum pressure, the dryness fraction of stream after the isentropic expansion...

For a given set of operating pressure limits of a Rankine cycle, the highest efficiency occurs for

The equivalent evaporation $$(kg/hr)$$ of a boiler producing $$2000$$ $$kg/hr$$ of steam with enthalpy content of $$2426$$ $$kJ/kg$$ from feed water at temperature $${40^ \circ }C$$ (liquid enthalpy $$=168$$ $$kJ/kg$$) i...

In a steam power plant operating with simple Rankine cycle, the turbine is fed with steam at $$100$$ bar and $$673$$ $$K.$$ Determine the actual enthalpy and quality of the steam extracted at $$14$$ bar if the turbine st...

Boiler rating is usually defined in terms of:

A steam turbine operating with less moisture is ____________ (more/less) efficient and ________ (less/more) prone to blade damage.

In stream and other vapor cycles, the process of removing non-condensables is called

Velocity compounded steam turbine known as ___________ (Curtis / Rateau ) turbine uses the principle of converting entire __________ (pressure / velocity) energy before entering the first stage runner itself.

In a Rankine cycle heat is added

In the Rankine cycle when super-heated steam is used:

A economizer in a steam generator performs the function of

The fundamental objective of employing the condenser in a steam power plant is to (reducce / increase ) the ______________of steam