Thermodynamics; Pressure and Temperature at the Nozzle inlet

In summary, the conversation discusses the determination of pressure at the nozzle inlet for CO2 gas that enters a nozzle with an isentropic efficiency of 83%. The gas exits the nozzle at 110 kpa, 59K, and 246m/s. The isentropic equation and the energy balance equation are used to solve for the inlet temperature and pressure. The concept of isentropic efficiency is also explained as a measure of deviation from isentropic processes.
  • #1
Sara1
12
0

Homework Statement


CO2 gas enters a nozzle with an isentropic efficiency of 83% with a low velocity. It exits the nozzle at 110 kpa and 59K and 246m/s. Determine the pressure at the nozzle inlet assuming:

Homework Equations


-Constant specific heats at room temperature
-Variable specific heats

The Attempt at a Solution


I first started by using the energy balance equation of a single stream steady flow device, and simplified it to:
Q=m(h2-h1) + 1/2(V2^2)

The isentropic equation is ηNozzle= (T2a-T1)/(T2s-T1)

I am at a loss in finding the inlet temperature and pressure. I am not sure how i should start of solving this question and what method to use.
 
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  • #2
Anyone know what "83% isentropic efficiency" means? That 17% of the heat escapes?
 
  • #3
Isentropic Efficiency= Measures the deviation of actual processes from the corresponding isentropic ones.

Thus, for a nozzle:

0.83= Actual Kinetic Energy at Nozzle Exit/ Isentropic KE at Nozzle Exit
 

FAQ: Thermodynamics; Pressure and Temperature at the Nozzle inlet

What is thermodynamics?

Thermodynamics is the branch of science that deals with the relationships between heat, energy, and temperature, and how these affect physical systems.

How does pressure affect the nozzle inlet?

Pressure at the nozzle inlet is crucial in determining the flow rate and velocity of a fluid passing through the nozzle. A higher pressure at the inlet will result in a faster flow rate and higher velocity, while a lower pressure will result in slower flow and lower velocity.

What is the ideal gas law and how does it relate to temperature and pressure?

The ideal gas law is a fundamental equation in thermodynamics that describes the relationship between pressure, volume, and temperature of an ideal gas. It states that at a constant temperature, the pressure and volume of an ideal gas are inversely proportional to each other. This means that as pressure increases, volume decreases and vice versa.

What is the significance of the nozzle inlet temperature in thermodynamics?

The temperature at the nozzle inlet is important because it affects the energy and heat transfer of the fluid passing through the nozzle. A higher temperature at the inlet will result in a higher energy and heat transfer, while a lower temperature will result in lower energy and heat transfer.

How does the nozzle inlet temperature and pressure affect the performance of a nozzle?

The temperature and pressure at the nozzle inlet have a direct impact on the performance of a nozzle. A higher temperature and pressure will result in a higher flow rate and velocity, while a lower temperature and pressure will result in slower flow and lower velocity. This can also affect the efficiency and effectiveness of the nozzle in various applications such as rocket engines and gas turbines.

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