Maximum Power Output of a Turbine

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To determine the maximum power output of an adiabatic turbine expanding argon gas from 3 MPa and 750°C to 0.2 MPa at a rate of 5 kg/s, the first step is to find the temperature at state two (T2) and the corresponding enthalpy (h2). The process is assumed to be isentropic, which simplifies calculations by allowing the use of initial conditions to derive final states. It's important to note that while the system is adiabatic, it is not closed, and temperature changes can occur. The final work output can be calculated using the mass flow rate and the difference in enthalpy (W = mass flow rate * (h1 - h2)). Understanding these principles is crucial for accurately solving the problem.
thermohelp12
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Hi,
I need with the following question.

Argon gas expands in an adiabatic turbine from 3MPa and 750 C to .2 MPa at a rate of 5 kg/s. Neglect KE and PE effects. Find maximum power output.

I know I need to first find the temperature of state two and then use that to solve for h2 (I have already solved for h1) then plug it into W=mass flow rate(h1-h2) to solve for the work and go from there but I am having a problem finding T2. Any help would greatly be appreciated.
 
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Welcome thermohelp12,

I think you need to make the assumption that the turbine is isentropic.

P.S. There is a HW help section of the forums.
 
thermohelp12 said:
Hi,
I need with the following question.

Argon gas expands in an adiabatic turbine from 3MPa and 750 C to .2 MPa at a rate of 5 kg/s. Neglect KE and PE effects. Find maximum power output.

I know I need to first find the temperature of state two and then use that to solve for h2 (I have already solved for h1) then plug it into W=mass flow rate(h1-h2) to solve for the work and go from there but I am having a problem finding T2. Any help would greatly be appreciated.

I think h2oski1326 was right you need to consider the isentropic process because according to your problem the gas expands in adiabatic process, that means you have a closed sytem, and if the system is closed there is no cahange in temperature. you can solved h2 using temperature from h1.
 
rodeliocueva said:
I think h2oski1326 was right you need to consider the isentropic process because according to your problem the gas expands in adiabatic process, that means you have a closed sytem, and if the system is closed there is no cahange in temperature. you can solved h2 using temperature from h1.

Turbines are open systems (i.e. control volumes).

A closed system does not necessarily mean that there is not a temperature change. An adiabatic system means that no heat is transferred across the system boundary. This is a common assumption (in homework problems) with turbines since they are normally well insulated.

BTW, this thread is 5 months old.

CS
 

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