- #1
HungryX2Hippo
Hey all. I feel like I understand the topic mathematically, but I have little intuition behind this. I like to try to think about what is going on at the molecular level. I've recently learned that the basis of lift that I was taught in class is not simply a pressure difference on the top and bottom side of the airfoil. It has come to make me question my knowledge...
My primary concern is how the turbine extracts temperature energy from the combustor. Pressure is as it is a force and can do work directly. Temperature in an open system isn't as intuitive. My question is how does the turbine extract the temperature energy (at the molecular level)? 99% of resources stop after saying "high pressure hot exhaust gases are expanded through the turbine. The other resources will just point at the equations, which are also not always intuitive. While the equations are derives form conservation laws, often mathematical tricks are employed to manipulate the equations and sometimes they lose their intuitive physical meaning.
As kind of a thought experiment if you had two chambers with a diaphragm and a turbine rotor separating them... If the pressure is higher in one chamber than the other (even if both are at the same temperature) when the diaphragm is ruptured the turbine would certainly start to turn as the fluid moved across it. However if you had a similar scenario with two chambers at the same pressure but different temperatures... I'm not sure the turbine would move.
Assuming the above is true... Then what part of the nozzle/rotor system in the turbine is responsible for converting that thermal energy and how exactly does it do it relative to the chamber experiment above.
Bonus question: Does the turbine get most of its lift via momentum transfer with the fluid (velocity triangles) or does it more have to do with the flow on the topside of the airfoil being faster than the bottom resulting in a dP that makes it rotate?
I apologize for the drawn out question!
My primary concern is how the turbine extracts temperature energy from the combustor. Pressure is as it is a force and can do work directly. Temperature in an open system isn't as intuitive. My question is how does the turbine extract the temperature energy (at the molecular level)? 99% of resources stop after saying "high pressure hot exhaust gases are expanded through the turbine. The other resources will just point at the equations, which are also not always intuitive. While the equations are derives form conservation laws, often mathematical tricks are employed to manipulate the equations and sometimes they lose their intuitive physical meaning.
As kind of a thought experiment if you had two chambers with a diaphragm and a turbine rotor separating them... If the pressure is higher in one chamber than the other (even if both are at the same temperature) when the diaphragm is ruptured the turbine would certainly start to turn as the fluid moved across it. However if you had a similar scenario with two chambers at the same pressure but different temperatures... I'm not sure the turbine would move.
Assuming the above is true... Then what part of the nozzle/rotor system in the turbine is responsible for converting that thermal energy and how exactly does it do it relative to the chamber experiment above.
Bonus question: Does the turbine get most of its lift via momentum transfer with the fluid (velocity triangles) or does it more have to do with the flow on the topside of the airfoil being faster than the bottom resulting in a dP that makes it rotate?
I apologize for the drawn out question!