Understanding Bird Strike on Planes
In this article, you will get info about Why and How Bird Strike on Planes? So let’s Start – Even today, most airplane pilots are terrified of an aerodynamic condition known as compressor stall. A minor incident, such as a bird striking a building, can set off this phenomenon. When a compressor stalls, the engine loses all thrust. Vibrations and loud bangs in the engine can have disastrous consequences, such as complete engine failure.
Let’s look at why compressors stall and how to avoid them. This image depicts the interior of an airplane engine. The fan compressors, combustion chamber, and turbines all run at the same time. Produce enough push to propel the plane forward. It’s worth noting that just a small part of the entering air enters the combustion chamber in a jet engine.
The rest of the engine is bypassed. A considerable portion of the air that enters the combustion chamber region is used to cool the combustion chamber rather than being burned. Let’s take a closer look at a specific aspect of this engine: the compressor. The compressor is the component that squeezes the incoming air and boosts its pressure significantly.
They do, in fact, give energy to the fluid. There are two compressor units on this engine. More information about the compressor may be found here. The stator blades are affixed to the casing and ensure that the airflow reaches the compressor rotor blades at the proper angle. The blades of the compressor rotor have an airfoil cross-section. To comprehend the physics of a compressor stall, you must first comprehend the physics of a compressor stall.
Let’s start by learning about the mechanics of airfoils. When fluid flows around an airfoil, it produces lift. The flow around the airfoil changes as the angle of attack varies. However, if you extend this angle beyond a certain point, the flow streamlines will begin to diverge. On the top surface of the airfoil, vortices form, and reverse flow occurs in this location. The airfoil has stalled in this location. It’s worth noting that with a rotating blade, the angle of attack is proportional to the blade’s velocity.
Consider the aftermath of a bird hit. The bird’s obstruction disrupts the flow pattern at the engine inlet and has the potential to substantially alter the flow angle of attack at the compressor inlet.
If this angle of attack is too high, flow reversal and compressor stall occur. When a compressor stalls, it is no longer able to drive incoming air into the combustion chamber, causing the chamber area to shrink. to be suddenly deprived of oxygen This means that the combustion chamber’s cooling is substantially diminished, and the temperature in this part of the engine rises dramatically. The important question is:
What happens to the compressor outlet pressure?
This can happen in one of two ways: it can either increase or diminish. Consider this experimental setup to learn about the properties of a compressor in order to get an answer to this query. The pressure versus mass flow graph will look like this if you use a cone to reduce the compressor mass flow rate. You can see how the pressure lowers after reaching peak pressure. This is because the compressor has stalled. a Low flow velocity might cause a high angle of attack, resulting in compressor stalling.
This graph is crucial to comprehend the effects of a compressor stall on an engine. Assume the initial compressor operating point is A, and the pointer changes to B due to the compressor stall. Here, the pressure at the compressor outlet decreases dramatically, and there is a significant decline in airflow; as a result, only a part of the fuel is burned. The extremely hot unburned fuel that leaves through the back of the combustion chamber will collide with the oxygen-rich Bypassed air, resulting in instantaneous combustion. Then there’s the second option.
Assume that the original operating point A shifts to Point C owing to stalling. The pressure rises abruptly at the compressor outlet, causing a tiny dip in the mass flow rate. In this situation, there is enough air for the complete burning of the fuel but not enough for adequate combustion chamber cooling. These conditions, along with the high pressure in the center of the engine, result in unexpected explosions, with exhaust escaping from both sides of the engine.
A compressor surge occurs when this process is repeated hundreds of times per second until pressure equilibrium is reached.
A compressor surge results in loud banging noises and strong vibrations in the engine. It can potentially lead to catastrophic engine failure if not properly handled. It’s fascinating to consider how the aftermath of a simple bird attack may result in such horrific events. Other factors that can cause a compressor to stall or surge are listed below. The big question here is how pilots can withstand such adversity. Some compressor stalls are self-stabilizing, but if they aren’t, they should intervene. Compressor stall is caused by an incorrect compressor blade angle of attack and an excessively rich fuel-to-air ratio.
As a result, by modifying these values, a compressor stall can be avoided. A variable can be seen. Most jet engines have a system of inlet guide vanes at the front. The angle of attack of the rotor blades can be greatly improved by adjusting the angle of these blades. In addition, bleed valves are used to blow air out and boost airflow. It will also significantly lessen the impact of a compressor stall. The alternative method is to adjust the throttle to limit the gasoline delivery. We hope you liked learning how a minor disturbance may cause massive instability in a jet engine. A revolving stall is another fascinating phenomenon related to this subject. We intend to release it as soon as possible.