I Steam flow rate in 2-chamber steam engine system

AI Thread Summary
The discussion focuses on a two-chamber steam engine system where heated air expands in the piston chamber (P2) to lift the piston. In phase 2, heated air escapes to the duct (P1) while heat continues to be supplied, affecting the volumetric flow rate as some energy is used for lifting the piston. Phase 3 involves cutting off the heat supply and locking the piston, allowing heat and vapor from P1 to flow back into P2. The main inquiry is about determining the steam flow rate entering P2 during phase 2 and when the piston is locked in phase 3. The conversation also touches on the boundary conditions of the system, confirming that P1 is at constant pressure.
Denniskwantas
Messages
3
Reaction score
0
Our system of interest has a duct on the left and a piston chamber on the right that make the shape of the letter T rotated 90º clockwise. The smaller tube on the left is abbreviated as P1 has an unspecified length while the piston chamber is P2. The air in P2 heats up and expands while the pressure remains constant (isobaric process). That said, heat energy (q) is supplied to the piston chamber to heat up the air and lift the piston up simultaneously.

In phase 2, the heated air escapes to P1 via the opening and heat energy is still supplied to the chamber to continue lifting the piston up. Caveat: The volumetric flow rate between P1 and P2 is not conserved because part of it goes to lifting the piston.

In phase 3, the heat supply is cut off and the position of the piston is locked in by some mechanism. The heat and vapor accrued in the isobaric expansion process in P1 will flow to P2.
1.jpg
2.jpg
3.jpg


The question is conceptual rather than finding the exact number. How can I find the flow rate of the steam as it enters P2 in phase 2 and when the piston's position is locked in phase 3 ?

Here are all the relevant equations, rewritten in LaTex.

Screen Shot 2021-10-23 at 9.40.19 AM.png


This is the general equation for mass flow rate which equals to the product of steam density, steam velocity and the area of the opening between P1 and P2 .

Recently I've found another equation for steam flow rate in a pipe.
https://www.physicsforums.com/attachments/291039

d : Pipe Inner Diameter (m)
v : Steam Velocity (m/s)
V : Specific volume (m³/kg)
m_s : Steam Flow Rate (kg/h)

Source: TLV
 
Physics news on Phys.org
You refer to air. Did you mean steam?
 
Yep. Steam it is. But it's not boiling steam though.
 
And what is the boundary condition at the far end of P1? Is it dead ended, or is it at constant pressure? Or something else?
 
As for the boundary conditions though, the P1 tube would be twice as long as P2 and yes, the P1 is at constant pressure with P2 as well.

I'm really interested in knowing whether the expansion of the heated moist air could lift the piston in P2 in any capacity.
 
Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
I know that mass does not affect the acceleration in a simple pendulum undergoing SHM, but how does the mass on the spring that makes up the elastic pendulum affect its acceleration? Certainly, there must be a change due to the displacement from equilibrium caused by each differing mass? I am talking about finding the acceleration at a specific time on each trial with different masses and comparing them. How would they compare and why?
This has been discussed many times on PF, and will likely come up again, so the video might come handy. Previous threads: https://www.physicsforums.com/threads/is-a-treadmill-incline-just-a-marketing-gimmick.937725/ https://www.physicsforums.com/threads/work-done-running-on-an-inclined-treadmill.927825/ https://www.physicsforums.com/threads/how-do-we-calculate-the-energy-we-used-to-do-something.1052162/
Back
Top