Can Any Genius Answer My Questions .can Any Body.

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Discussion Overview

The discussion revolves around calculating the thermal efficiency of a petrol engine based on given dimensions, including stroke length, bore, and clearance volume. The inquiry seeks to understand the relationship between these parameters and thermal efficiency, touching on theoretical and practical aspects of engine performance.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant questions the sufficiency of the provided information for calculating thermal efficiency.
  • Another participant asserts that operating temperatures are necessary to determine thermal efficiency, suggesting that a significant temperature difference between thermal reservoirs enhances efficiency.
  • A formula for thermal efficiency is proposed, relating it to the compression ratio, with the equation thermal efficiency = 1 - C^(1-k), where k is dependent on operating temperatures.
  • A different participant provides a method to calculate the compression ratio using displacement volume and clearance volume, leading to another equation for thermal efficiency: η=1-(1/r^(k-1)).

Areas of Agreement / Disagreement

Participants do not reach a consensus on the sufficiency of the information provided or the necessity of operating temperatures for calculating thermal efficiency. Multiple viewpoints regarding the approach to the problem remain present.

Contextual Notes

The discussion highlights limitations in the information provided, such as the absence of operating temperatures and the need for clear definitions of terms like displacement volume and clearance volume.

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Question :

Find out thermal efficiency of a petrol engine having the following dimensions.Stroke length of piston is 75mm .Bore (internal diameter)=50mm and clearance colume is 21.3centimer cube.



please please tell me the solution please if u are genius then please answer this
 
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Although this isn't my area, I have serious doubts about there being anywhere near enough information there for an answer.
 
It is not possible to find the thermal efficiency without any knowledge of the operating temperatures. It is far easier to get work done when there is a large difference in temperature between your two thermal reservoirs. You can deduce a relationship however between the efficiency and compression ratio.

The compression ratio is the ratio between the pistol's stroke volume over the clearance volume. If the compression ratio can be denoted by C, then

thermal efficiency = 1 - C^(1-k)
where k depends on the operating temperatures of the heat-work cycle.
 
Have a look at this solution

Aslamoalaikum!

see how to solve this question.
Bore=D
Stroke=L
Displacement volume=[tex]\pi\frac{D^2}{4}L[/tex]
Clearance Volume= 21.3 cubic millimeter

Now you can write

r= displacement vol / clearance vol

once you find the value of r

you can use the following equation

[tex]\eta=1-\frac{1}{r^{k-1}}[/tex]
 
Last edited:

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