Which one of the following quantities is assumed constant for an inter...
Introduction:
In the estimation of friction power in an internal combustion engine using the Willans line, it is assumed that the indicated thermal efficiency remains constant. The Willans line is a graphical representation of the relationship between the indicated thermal efficiency and the friction power in an engine.
Explanation:
1. Willans Line:
The Willans line is a plot of the indicated thermal efficiency against the friction power in an internal combustion engine. It is used to estimate the friction power by extrapolating the line to zero indicated thermal efficiency.
2. Friction Power:
Friction power is the power consumed by the engine to overcome the internal friction within its components such as the piston rings, bearings, and valve train. It is a parasitic power loss that reduces the overall efficiency of the engine.
3. Indicated Thermal Efficiency:
Indicated thermal efficiency is a measure of how effectively the engine converts the energy in the fuel into useful work. It is the ratio of the indicated work to the energy input from the fuel. It accounts for both the useful work done by the engine and the energy lost as waste heat.
4. Constant Indicated Thermal Efficiency:
When estimating the friction power using the Willans line, it is assumed that the indicated thermal efficiency remains constant. This assumption is based on the fact that the friction power primarily depends on the design, materials, and lubrication of the engine components, rather than the combustion process.
5. Other Quantities:
The other quantities mentioned in the options, namely brake thermal efficiency, mechanical efficiency, and volumetric efficiency, are not assumed to be constant while estimating the friction power using the Willans line. These quantities can vary based on factors such as load, speed, and engine condition.
Conclusion:
In conclusion, the indicated thermal efficiency is assumed to be constant while estimating the friction power using the Willans line in an internal combustion engine. This assumption allows for a simplified estimation of the friction power based on the graphical relationship between the indicated thermal efficiency and the friction power.
Which one of the following quantities is assumed constant for an inter...
B
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