Design of Fan for Turbofan engine

In summary, the Turbofan design project is going well. I followed the GFCR Rogers, HISH Saravanamuttoto, and HCohen book to determine the pitch to chord ratio for five points from hub to tip. However, I am having difficulty determining the pitch to chord ratio past the value of air deflection in the graph. I am also trying to find a guide for drawing blade profiles and varying the inlet and outlet angles for blade from hub to tip.
  • #1
Johnny99
5
0
I currently doing by final project about designing fan for turbofan engine.After discussing with my lecturer,I decided to do it based on axial compressor preliminary design method in Gas Turbine Theory : G. F. C. Rogers, H. I. H. Saravanamuttoo, Henry Cohen book.Now after following the design method,I'm stucked at determining the pitch to chord ratio for five points from hub to tip.According to the book,it is determined from the graph Air deflection versus air outlet angle in Fig 5.14 pp139 but i got the air deflection beyond the the value of the air deflection in the graph.I tried searching for the bigger graph but no luck.

Your helps is very appreciated.
 
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  • #2
anyone? at least give some reference to design the fan ..I 'm really confused right now finding suitable design method for this..please help me...:cry:
 
  • #3
As a turbine mechanic I can say that having a even number of blades would be greatly appreciated. This make repairs and balancing much easier. This probably doesn't help at all.
 
  • #4
That's kind of funny, because as a turbomachinery engineer, we prefer to have the number of blades odd and prime if possible.
 
  • #5
Thanks for reply guys although it seems not related to my question.At first I followed McKenzie method to determine the pitch chord ratio but I got weird blade shape.It has very small chord at hub and very large at mean radius and become smaller at tip.I end up assuming pitch to chord ratio is equal to 1 from hub to tip.so now I got blade chord increase from hub to tip.As for what you guys discussed,from my reading,for rotor ,it is preferred to have odd and prime number of blade to avoid resonance while in stator it is preferred for it to be even.Now I got new problem on how to draw my blade and do cfd analysis for it using ansys cfx.I tried googling but there are not enough guide for it.I tried using ansys bladegen software but not quite understand how can I draw naca profile blade and vary the inlet and outlet angle for it from hub to tip.Any guide for this subject is really appreciated.
 
  • #6
Johnny99 said:
Thanks for reply guys although it seems not related to my question.At first I followed McKenzie method to determine the pitch chord ratio but I got weird blade shape.It has very small chord at hub and very large at mean radius and become smaller at tip.I end up assuming pitch to chord ratio is equal to 1 from hub to tip.so now I got blade chord increase from hub to tip.As for what you guys discussed,from my reading,for rotor ,it is preferred to have odd and prime number of blade to avoid resonance while in stator it is preferred for it to be even.Now I got new problem on how to draw my blade and do cfd analysis for it using ansys cfx.I tried googling but there are not enough guide for it.I tried using ansys bladegen software but not quite understand how can I draw naca profile blade and vary the inlet and outlet angle for it from hub to tip.Any guide for this subject is really appreciated.

Really, I didn't know that there is was a reason for the odd number of blades. I know that the GE engines that the Army uses have an even number of blades to ease repairs when a blade is chipped or worn. (You only have to file the blade on the opposite side to balance as opposed to balancing all the blades.) I imagine I'll learn more about this in my future studies. Good luck with your work. I hope it goes well.
 

1. How does the design of a fan affect the performance of a turbofan engine?

The design of the fan is crucial to the performance of a turbofan engine. The fan is responsible for providing the majority of the thrust, and its design determines the amount of air that can be ingested and accelerated by the engine. A well-designed fan can increase the efficiency and power output of the engine, while a poorly designed fan can lead to decreased performance and potential engine failure.

2. What factors are considered when designing a fan for a turbofan engine?

There are several factors that must be taken into account when designing a fan for a turbofan engine. These include the desired thrust output, air flow rate, engine size and weight, fuel consumption, and noise levels. The materials used for the fan blades and their shape and size must also be carefully considered to ensure optimal performance and durability.

3. How does the number of fan blades affect the design of a turbofan engine?

The number of fan blades is an important consideration in the design of a turbofan engine. A higher number of blades can increase the engine's overall efficiency by providing more surface area for air to be accelerated. However, too many blades can also add weight and complexity to the engine, so a balance must be struck between performance and practicality.

4. What role do computer simulations play in the design process of a fan for a turbofan engine?

Computer simulations are an essential tool in the design process of a fan for a turbofan engine. They allow engineers to test and optimize various design parameters, such as blade shape and angle, without the need for physical prototypes. This saves time and resources and allows for more efficient and accurate designs.

5. How has the design of fans for turbofan engines evolved over time?

The design of fans for turbofan engines has evolved significantly over time. In the early days of aviation, fans were simple and had a low number of blades. As technology advanced, fans became more complex and efficient, with higher blade counts and improved aerodynamics. Today, with the use of advanced materials and computer simulations, fans are designed to be even more efficient, lightweight, and durable, contributing to the overall advancements in aviation technology.

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