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Leakage of Freon-12 can't obtain TOTAL CONCENTRATION but it has all DESIRABLE characteristics as GOOD REFRIGERANT.

Leakage of Freon-12 can't obtain total concentration but it has all desirable characteristics as good refrigerant.

Condensing pressure of R22 at any GIVEN TEMPERATURE is higher than that of R12.

Condensing pressure of R22 at any given temperature is higher than that of R12.

Overall heat TRANSFER COEFFICIENT can be increased by INCREASING velocity of water in tube. Further STEAM needs more space due to higher specific volume.

Overall heat transfer coefficient can be increased by increasing velocity of water in tube. Further steam needs more space due to higher specific volume.

Material with LOWER thermal conductivity should be USED for INNER layer and material with higher thermal conductivity for the outer layer.

Material with lower thermal conductivity should be used for inner layer and material with higher thermal conductivity for the outer layer.

For REGENERATIVE cycle which approaches CARNOT cycle. 1

For regenerative cycle which approaches Carnot cycle. 1

COP of REFRIGERATOR = COP of HEAT PUMP -1.

COP of refrigerator = COP of heat pump -1.

T2/TX.

T2/TX.

CONSTANT VOLUME.

Constant volume.

In general, the THINNER the boundary layer, HIGHER the value of LOCAL heat TRANSFER film coefficient.

In general, the thinner the boundary layer, higher the value of local heat transfer film coefficient.

In LAMINAR flow, boundary layer extends right from surface upto centre. In FULLY TURBULENT it may extend 5-10% of RADIUS only whereas in transition flow, boundary layer may be from 50-60% of radius of pipe.

In laminar flow, boundary layer extends right from surface upto centre. In fully turbulent it may extend 5-10% of radius only whereas in transition flow, boundary layer may be from 50-60% of radius of pipe.

TWO TIMES the ENGINE SPEED.

Two times the engine speed.

It REMAINS CONSTANT.

It remains constant.

THERMAL N of both will be same.

Thermal n of both will be same.

In EASE of turbulent boundary layer, boundary layer thickness is defined as the distance from solid surface at which the fluid VELOCITY is 99% of the UNDISTURBED free stream velocity. Near the surface of solid, there is laminar flow which CHANGES to buffer zone and FINALLY turbulent region.

In ease of turbulent boundary layer, boundary layer thickness is defined as the distance from solid surface at which the fluid velocity is 99% of the undisturbed free stream velocity. Near the surface of solid, there is laminar flow which changes to buffer zone and finally turbulent region.

hotter.

hotter.

- 2°C.

- 2°C.

Because the mean TEMPERATURE of heat ADDITION is HIGHER for superheat CYCLE.

Because the mean temperature of heat addition is higher for superheat cycle.

Ambient conditions, inlet/ EXHAUST pressure losses, fuels, and WATER/ STEAM injection flow RATES' influence the performance of GAS turbines.

Ambient conditions, inlet/ exhaust pressure losses, fuels, and water/ steam injection flow rates' influence the performance of gas turbines.

Various parameters affecting HEAT RATE of GT are :

1. Lower the gas turbine INLET temperature, lower the heat rate.
2. HIGHER the compression ratio, lower the heat rate.
3. Higher the turbine firing temperature, lower the heat rate.
4. Lower the exhaust temperature, lower the heat rate.
5. Exhaust gas flow, inlet pressure loss, exhaust pressure loss ALSO affect heat rate.

Various parameters affecting heat rate of GT are :

ISO conditions for GT performance are : Ambient dry bulb TEMPERATURE : 15°C, RELATIVE HUMIDITY - 60%. Ambient barometric PRESSURE 1.0 kg/cm2.

ISO conditions for GT performance are : Ambient dry bulb temperature : 15°C, Relative humidity - 60%. Ambient barometric pressure 1.0 kg/cm2.

Catalytic OXIDATION, a post combustion treatment at 470°-600° temperature is USED to REDUCE emission of CO and VOCs.

Catalytic oxidation, a post combustion treatment at 470°-600° temperature is used to reduce emission of CO and VOCs.

V2O5 supported by titanium or a MIXTURE of titanium and SILICA is generally used as CATALYST. Oxides of Ti and Mo are often incorporated as MODERATORS.

V2O5 supported by titanium or a mixture of titanium and silica is generally used as catalyst. Oxides of Ti and Mo are often incorporated as moderators.

SCR is a POST combustion method in which a catalyst is installed in flue gas where temperature could be of the order of 15-400°C. It enables vaporised NH to react with NO* in exhaust gas to form N2 and H20. Vaporised NH is injected into exhaust gases before it PASSES through the catalyst bed. This process can ACHIEVE in excess of 90% NOX reduction.

SCR is a post combustion method in which a catalyst is installed in flue gas where temperature could be of the order of 15-400°C. It enables vaporised NH to react with NO* in exhaust gas to form N2 and H20. Vaporised NH is injected into exhaust gases before it passes through the catalyst bed. This process can achieve in excess of 90% NOx reduction.

Dry low NOX combustors RESULT in improved air/fuel mixing and reduced flame temperature. The main type are lean premixed combustors, rich/quench lean combustors and catalytic combustors. Variable guide vanes are USED to CONTROL the fuel-air mixture. In one design combustion chamber is designed into a series of SMALL, lean premixed chambers.

Dry low NOx combustors result in improved air/fuel mixing and reduced flame temperature. The main type are lean premixed combustors, rich/quench lean combustors and catalytic combustors. Variable guide vanes are used to control the fuel-air mixture. In one design combustion chamber is designed into a series of small, lean premixed chambers.

Water/steam is injected to LIMIT the AMOUNT of NOx formed by lowering the FLAME and GAS temperatures.

Water/steam is injected to limit the amount of NOx formed by lowering the flame and gas temperatures.

• INCREASED CO at lower loads
• Increased fuel consumption
• LOSS of EXTENSIVELY treated water
• Increased complexity of engine control
• SHORT LIFE of major turbine components.

It LOWERS the FLAME and GAS TEMPERATURES.

It lowers the flame and gas temperatures.

Fuel NO* is formed by the GAS PHASE oxidation of CHAR NITROGEN (CN~ compounds) in the fuel and thermal NO* is formed by high TEMPERATURE reaction between the nitrogen and oxygen in the combustion air.

Fuel NO* is formed by the gas phase oxidation of char nitrogen (CN~ compounds) in the fuel and thermal NO* is formed by high temperature reaction between the nitrogen and oxygen in the combustion air.

NO* in GAS turbines is controlled by

1. INJECTING water/steam into combustor,
2. using selective CATALYTIC REDACTION (SCR) and non-catalytic reduction system (NRS), and
3. better combustor design.

NO* in gas turbines is controlled by

It can be INCREASED by generating steam at more than one pressure.

Further improvement is possible by heating make up WATER/condensate in HRSG, generating LOW pressure saturated steam or deaeration steam in HRSG using a low pressure evaporator, preheating the make up water in a heat ex-changer before it enters deaerator, and CIRCULATE more water than necessary through the economizer and RECIRCULATE excess to the deaerator.

It can be increased by generating steam at more than one pressure.

Further improvement is possible by heating make up water/condensate in HRSG, generating low pressure saturated steam or deaeration steam in HRSG using a low pressure evaporator, preheating the make up water in a heat ex-changer before it enters deaerator, and circulate more water than necessary through the economizer and recirculate excess to the deaerator.

Centrifugal compressors have following advantages :

• short length due to high pressure ratio obtained in a single stage.
• simple in design, easy to manufacture, rugged in construction, less costly.
• more reliable in operation under all operating condition.
• less susceptible to the effects of DEPOSITS LEFT on flow path.
• less sensitive to the FOULING of the flow path.
• Good efficiency over a wide range of operation.

Drawback is larger cross-section area for same capacity and its unsuitability for high pressure RATIOS. Axial flow compressor is more popular due to high delivery capacity, high compression ratio due to many stages, high efficiency (85-90%), low cross sectional area. Its drawback is sophisticated design and APPRECIABLE length due to large number of stages, narrow operating range for good efficiency, higher weight and cost, high starting power.

Centrifugal compressors have following advantages :

Drawback is larger cross-section area for same capacity and its unsuitability for high pressure ratios. Axial flow compressor is more popular due to high delivery capacity, high compression ratio due to many stages, high efficiency (85-90%), low cross sectional area. Its drawback is sophisticated design and appreciable length due to large number of stages, narrow operating range for good efficiency, higher weight and cost, high starting power.

Water/steam INJECTION is not allowed beyond 5% of COMPRESSOR flow to avoid FLAME out in combustion and to minimise operating COST and impact on inspection INTERVALS.

Water/steam injection is not allowed beyond 5% of compressor flow to avoid flame out in combustion and to minimise operating cost and impact on inspection intervals.

WATER injection results in higher mass flow rate through turbine section and as RICH electrical output is increased. However it increases gas turbine heat rate because of the additional heat consumption required to VAPORISE the water.

Steam injection increases POWER output and DECREASES heat rate because of its higher energy entering the combustion zone.

Water injection results in higher mass flow rate through turbine section and as rich electrical output is increased. However it increases gas turbine heat rate because of the additional heat consumption required to vaporise the water.

Steam injection increases power output and decreases heat rate because of its higher energy entering the combustion zone.

INDEPENDENT of WAVELENGTH.

Independent of wavelength.

When convection HEAT TRANSFER OCCURS between a solid body and a FLUID and where circulation of fluid is CAUSED and controlled by some mechanical.

When convection heat transfer occurs between a solid body and a fluid and where circulation of fluid is caused and controlled by some mechanical.

Velocity of fluid FLOW at SOLID surface is zero and it INCREASES rapidly as distance from solid surface becomes greater, reaches a maximum value and then decreases to that of undisturbed fluid. The distance between the solid surface and point where boundary layer velocity equals undisturbed flow (EDGE) is called boundary layer thickness.

Velocity of fluid flow at solid surface is zero and it increases rapidly as distance from solid surface becomes greater, reaches a maximum value and then decreases to that of undisturbed fluid. The distance between the solid surface and point where boundary layer velocity equals undisturbed flow (edge) is called boundary layer thickness.

As pressure is INCREASED, the dryness fraction of steam lowers on isentropic EXPANSION. Therefore, steam has to be reheated after partial expansion so that dryness fraction remains WITHIN limits after expansion.

As pressure is increased, the dryness fraction of steam lowers on isentropic expansion. Therefore, steam has to be reheated after partial expansion so that dryness fraction remains within limits after expansion.

It will DECREASE.

It will decrease.

EFFECTIVENESS of heat exchanger = ACTUAL heat transfer/maximum POSSIBLE heat transfer.

Effectiveness of heat exchanger = actual heat transfer/maximum possible heat transfer.

DIAGRAM EFFICIENCY = CHANGE in K.E./kg / ENERGY supplied/kg.

Diagram efficiency = Change in K.E./kg / Energy supplied/kg.

It refers to AMOUNT of UNEVAPORATED moisture in STEAM. If steam is perfectly DRY, it's quality is 100%.

It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.

100 TIMES the space OCCUPIED by 1 kg of water.

100 times the space occupied by 1 kg of water.

Zero.

Zero.

At 225 kg/cm2 and 74.6° C.

At 225 kg/cm2 and 74.6° C.

The velocity of steam decreases in successive STAGES and to accommodate same flow per unit TIME, the AREA of flow must increase.

The velocity of steam decreases in successive stages and to accommodate same flow per unit time, the area of flow must increase.

Percentage of U25 in natural URANIUM is INCREASED by a PROCESS called uranium enrichment.

Percentage of U25 in natural uranium is increased by a process called uranium enrichment.

FAST BREEDER REACTOR.

Fast breeder reactor.

For critical CONDITION, the reaction should continue at a steady RATE which is possible when rate of PRODUCTION of NEUTRONS is same as the combined rate of absorption of neutrons and the rate of LEAKAGE of neutrons.

For critical condition, the reaction should continue at a steady rate which is possible when rate of production of neutrons is same as the combined rate of absorption of neutrons and the rate of leakage of neutrons.

DIESEL ENGINE POWER PLANT.

Diesel engine power plant.

NATURAL URANIUM.

Natural uranium.