What affects specific fuel consumption?

What affects specific fuel consumption?

SFC varies with throttle setting, altitude, climate. For jet engines, air flight speed is an important factor too. Air flight speed counteracts the jet’s exhaust speed.

How does thrust specific fuel consumption CT vary with altitude?

According to the Aerodynamic text-How does Thrust Specific Fuel Consumption (Ct) vary with altitude? Thrust Specific Fuel Consumption does not change with altitude. Thrust Specific Fuel Consumption decreases with increases in altitude. Thrust Specific Fuel Consumption is equal to thrust.

How do you define specific fuel consumption?

Specific fuel consumption is the amount of fuel consumed by a vehicle for each unit of power output. A vehicle’s specific fuel consumption is more or less independent from its nitrogen oxide emissions per kilometer. The specific fuel consumption of an engine is the rate of fuel burnt to produce a unit of thrust.

What is mean by specific fuel consumption?

We then define specific fuel consumption (SFC) as the quantity of fuel burned in unit time required to produce a given engine output. SFC is a technical figure of merit that indicates how efficiently the engine converts fuel into power.

Do you know the relationship between thrust and fuel consumption?

Although a knowledge of the inner workings of an aircraft engine is not necessary, the functional relationships for the propulsive force (the thrust T) and the fuel consumption rate, along with a feel for the weight of the engine per pound of thrust or horsepower, are required for performance analyses and preliminary design studies.

How is the thrust of a jet engine determined?

Is the mass of fuel needed to provide the net thrust for a given period, specific fuel consumption of air-breathing jet engines at their maximum efficiency is more or less proportional to speed, it varies with throttle setting, altitude and climate

How does SFC affect the thrust of an engine?

SFC is a measure of fuel consumed per thrust produced. As altitude increases air mass flow into engine decreases, thrust also decreases for same throttle setting. For example at 33000 ft engine will produce only one-third thrust compared to SL. Since air mass flow rate decreases fuel flow is also reduced proportionately by engine control system.

What happens to thrust and SFC at altitude?

When both thrust and fuel flow are reduced, SFC should remain literally constant. But combustion efficiency deteriorates with altitude which requires more fuel to produce same energy than at lower altitude. So, SFC increases at altitude. Specific fuel consumption is the amount of fuel consumed by a vehicle for each unit of power output.