How Do You Calculate Thermal Efficiency in a Diatomic Gas Heat Engine Cycle?

In summary, the problem involves building a heat engine using an ideal diatomic gas and going through a cycle that includes an isobaric and isochoric segment. The task is to calculate the thermal efficiency of the engine, which can be done using the formula e = W/Q_H = 1 - |Q_C/Q_H|. The values needed for the calculations are provided in the problem. The student initially struggles with finding the appropriate equation to use, but eventually realizes that they can use the heat transfer equation for the isobaric segment to solve for Q_H.
  • #1
Eagle's Wings
17
1

Homework Statement



You build a heat engine that takes 1.00 mol of an ideal diatomic gas through the cycle abc, where segment bc is isobaric and segment ca is isochoric. calculate the thermal efficiency of the engine.

this is a 5 part problem and I already solved for Wo and Wo=Qo I solved for Ta, Tb, and Tc. Ta=Tb. the problem gives me Va, Vb, Pa, and Pb in the figure.

Homework Equations



e = W/Q[itex]_{H}[/itex] = 1 - |Q[itex]_{C}[/itex]/Q[itex]_{H}[/itex]|

W = |Q[itex]_{H}[/itex]| - |Q[itex]_{C}[/itex]|

The Attempt at a Solution



I know that there are other ways to solve for e, but I don't know how to solve for e in this problem. I am completely lost. I can't use Carnot because that's for an ideal system, I can't use the one for the otto cycle because i don't have r and the problem doesn't tell me that it is otto cycle problem. WHAT DO I DO?
 
Physics news on Phys.org
  • #2
also the segment ab is isothermic. I don't see how that would help any though
 
  • #3
just kidding, i just figured it out. i can use the equation of heat entering the system which is Qh which is on segment bc which is isobaric so i can use Cp to solve for Qh!
 

FAQ: How Do You Calculate Thermal Efficiency in a Diatomic Gas Heat Engine Cycle?

1. What is thermal efficiency?

Thermal efficiency is a measure of the effectiveness of a heat engine in converting heat into work. It is the ratio of the work output to the heat input, expressed as a percentage.

2. How is thermal efficiency calculated?

Thermal efficiency is calculated by dividing the work output by the heat input and multiplying by 100%. The heat input can be measured in Joules, while the work output is typically measured in Watts or horsepower.

3. What factors affect thermal efficiency?

The factors that affect thermal efficiency include the design and condition of the heat engine, the type of fuel used, the temperature of the heat source, and the temperature of the heat sink.

4. Why is thermal efficiency important?

Thermal efficiency is important because it allows us to measure the performance of a heat engine and determine how much energy is being wasted during the conversion process. It also helps us to identify ways to improve the efficiency of heat engines, leading to cost savings and reduced environmental impact.

5. How can thermal efficiency be improved?

Thermal efficiency can be improved by reducing heat losses, increasing the temperature difference between the heat source and heat sink, and using more efficient heat engines and fuels. Regular maintenance and proper operation of heat engines can also help improve efficiency.

Back
Top