Understanding Brayton Cycle Temperatures: Finding Outlet Flow Rate"

In summary, the conversation discusses a general concern with finding temperature values at different processes in a cycle. The speaker is stuck on an example and is wondering which temperatures they need to put in the SFEE. They mention that their guess is T4 - T1 and they are unsure how to calculate temperature 3 and 4, particularly on the constant pressure line. They list the information they have, including shaft power, inlet velocity, mass flow rate, pressures, cp, gamma, and temperature at inlet. They ask for help as they have an exam tomorrow and this is their only sticking point. They also mention that the temperature given to them may be T3 in the cycle and not the compressor temperature. They hope that their question is not
  • #1
grolschey
2
0
This is a general concern with finding temperature values at different processes in the cycle, however i do have an example i am stuck on, and can post that if needs be. anyway, if i was required to find the flow rate at outlet, which temperatures would i need to put in the SFEE as i know cp(deltaT) = deltaH, my guess is T4 - T1. how would i go about getting temperature 3 and 4, I can get temperature 2 no problem, my main problem lies with calculating T3 on the constant pressure line, there is no volumes given and neither is the heat input at constant pressure. I basically have the shaft power, the inlet velocity, the mass flow rate, the pressures, cp and gamma, and temperature at inlet, which i assume is T1...?

any help would be great, as i have an exam tomorrow and this seems to be the only sticking point for me.

Thanks in advance

Edit: It has come to my attention that this may well come under the subject of homework-type questions. however as i am not sure, and it seems pretty general to me, i will leave it here which i hope is not to much of a problem, and if required i or a moderator can move the post. :)
 
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  • #2
nevermind the temperature it has given me is T3 in the cycle, i believe its the turbine inlet conditions given, rather than the compressor, as if it was i would need a max cycle temp to work out the other unkowns.
 

FAQ: Understanding Brayton Cycle Temperatures: Finding Outlet Flow Rate"

What is a Brayton Cycle and how does it work?

The Brayton Cycle is a thermodynamic cycle used in gas turbines to convert heat energy into mechanical work. It consists of four main processes: compression, heating, expansion, and cooling. In this cycle, air is compressed, heated, and then expanded to drive a turbine and produce power.

Why is understanding Brayton Cycle temperatures important?

Understanding the temperatures in the Brayton Cycle is crucial for determining the efficiency of the cycle and ensuring that the turbine operates within safe temperature limits. It also helps in optimizing the cycle for maximum power output.

What is the outlet flow rate and how is it calculated in the Brayton Cycle?

The outlet flow rate is the amount of air flowing out of the turbine in a given amount of time. It is calculated by dividing the mass flow rate by the density of the air. The mass flow rate can be calculated using the ideal gas law and the density can be determined using the ideal gas law or from tables.

How do variations in inlet conditions affect Brayton Cycle temperatures and outlet flow rate?

Variations in inlet conditions, such as changes in temperature or pressure, can significantly impact the temperatures and outlet flow rate in the Brayton Cycle. This is because these variations affect the efficiency of the cycle and the amount of heat energy available for conversion. As a result, it is important to carefully control and monitor the inlet conditions to ensure optimal performance of the cycle.

What are some factors that can affect the accuracy of calculations in understanding Brayton Cycle temperatures and outlet flow rate?

Some factors that can affect the accuracy of calculations include assumptions made in the models used to analyze the cycle, variations in gas properties, and losses in the system. It is important to consider these factors and make appropriate adjustments to obtain more accurate results. Additionally, using more advanced modeling techniques and accurate data can also improve the accuracy of the calculations.

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