# Thermodynamics - Entropy generation Q

• DrVirz
Hi all,Just doing some thermo study and am stuck on a question. I am not sure where to start this Q as normally I am given a property at the exit..?Any help is appreciated.In summary, the conversation is about a question regarding a co-current heat exchanger where both fluids are flowing in the same direction. The solution involves setting the enthalpy increase for the oxygen stream equal to the enthalpy decrease for the nitrogen stream to determine the exit temperature of both gases. The calculation of entropy change per kg of a gas is also discussed, with the reminder that pressure effects can be neglected. The question asks for the entropy change per kg of oxygen and nitrogen passing through the heat exchanger.
DrVirz
Hi all,

Just doing some thermo study and am stuck on a question. I am not sure where to start this Q as normally I am given a property at the exit..?

Any help is appreciated.

This is a co-current heat exchanger, and both fluids are flowing in the same direction. So, you need to set the enthalpy increase for the oxygen stream equal to the enthalpy decrease for the nitrogen stream. This will give you the exit temperature of both gases. So you know the starting temperature of each gas and the exit temperature of each gas. Do you know how to calculate the entropy change per kg of a gas if you know its initial temperature and its final temperature? (You don't have to take into consideration the effect of pressure on the entropy of each gas, because you are told that the pressure drops of the two gases are negligible). If so, what is the entropy change per kg of the oxygen and of the nitrogen in passing through the heat exchanger?

Chet

## What is entropy?

Entropy is a measure of the disorder or randomness of a system. It is a thermodynamic property that reflects the amount of energy that is unavailable for work in a thermodynamic process.

## How is entropy related to thermodynamics?

Entropy is a fundamental concept in thermodynamics, which is the study of energy and its transformations. It is one of the laws of thermodynamics that states that the total entropy of an isolated system always increases over time.

## What is entropy generation?

Entropy generation is the process by which entropy is produced in a system. It is a measure of the irreversible loss of energy during a thermodynamic process.

## What factors affect entropy generation?

Entropy generation is affected by a number of factors, including temperature, pressure, and the type of process being studied. It is also influenced by the efficiency of the system and any external sources of energy.

## How is entropy generation calculated?

The calculation of entropy generation involves using the first and second laws of thermodynamics to determine the change in entropy of a system. It can be calculated using various thermodynamic equations and principles, depending on the specific system and process being studied.

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