# بحث بالانجليزي عن محركات الطائرات وانواعها و تصاميمها



## amna25 (28 مايو 2011)

السلام عليكم...

مهندسين بليز انا هندسه صناعيه والدكتور معطينا بحث في اخر يوم دراسه عليه 10 درجات عن محركات الطائرات وانواعها وتصاميمها بس ابيه (بالانجلش ) بحثت بالنت بس اصلا انا مو فاهمه الموضوع ولا عمرنا درسنا عنه ....

بلييييييزززززز ساعدوني اذا تعرفون مواقع موثوقه او كتب او اي اي اي شي ساااعدوني ...والحين بدينا امتحانات والوقت ضيق وانتوا اعلم ......:80::80::80::80:


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## سامح الفيومى (29 مايو 2011)

*أولا تعريف دفع الطائرات*

Thrust is the force which moves any aircraft through the air. Thrust is generated by the propulsion system of the aircraft. Different propulsion systems develop thrust in different ways, but all thrust is generated through some application of Newton's third law of motion. For every action there is an equal and opposite reaction. In any propulsion system, a working fluid is accelerated by the system and the reaction to this acceleration produces a force on the system. A general derivation of the thrust equation shows that the amount of thrust generated depends on the mass flow through the engine and the exit velocity of the gas.

During World War II, a new type of airplane engine was developed independently in Germany and in England. This engine was called a gas turbine engine. We sometimes call this engine a jet engine. Early gas turbine engines worked much like a rocket engine creating a hot exhaust gas which was passed through a nozzle to produce thrust. But unlike the rocket engine which must carry its oxygen for combustion, the turbine engine gets its oxygen from the surrounding air. A turbine engine does not work in outer space because there is no surrounding air. For a gas turbine engine, the accelerated gas, or working fluid, is the jet exhaust. Most of the mass of the jet exhaust comes from the surrounding atmosphere. Most modern, high speed passenger and military aircraft are powered by gas turbine engines. Because gas turbine engines are so important for modern life, we will be providing a lot of information about turbine engines and their operation.

Turbine engines come in a wide variety of shapes and sizes because of the many different aircraft missions. All gas turbine engines have some parts in common, however. On the slide we see pictures of four different aircraft equipped with gas turbine engines. Each aircraft has a unique mission and therefore a unique propulsion requirement. At the upper left is a DC-8 airliner. Its mission is to carry large loads of passengers or cargo for a long distance at high speed. It spends most of its life in high speed cruise. At the lower left is an F-14 fighter plane. Its mission is to shoot down other aircraft in air-to-air combat. It spends most of its life in cruise, but needs high acceleration when in combat. At the lower right is a C-130 cargo aircraft. Like the DC-8, it carries cargo a long distance, but it does not have the high speed requirement of the DC-8. At the upper right is a T-38 trainer. It is used to teach pilots how to fly jet aircraft and does not have the acceleration requirements of the F-14. The DC-8 is powered by four high-bypass turbofan engines, the F-14 by two afterburning low-bypass turbofans, the C-130 by four turboprop engines, and the T-38 by two turbojet engines.

EngineSim is an interactive Java applet which allows you to study different types of jet engines. You can learn the fundamentals of turbine engine propulsion with the EngineSim simulator. RangeGames is an interactive Java applet which allows you to study how different types of aircraft use different types of engines to meet their mission.


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## سامح الفيومى (29 مايو 2011)

*انواع المحركات*


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## سامح الفيومى (29 مايو 2011)

*الأنواع مع الشرح*

Jet engines move the airplane forward with a great force that is produced by a tremendous thrust and causes the plane to fly very fast.

All jet engines, which are also called gas turbines, work on the same principle. The engine sucks air in at the front with a fan. A compressor raises the pressure of the air. The compressor is made up of fans with many blades and attached to a shaft. The blades compress the air. The compressed air is then sprayed with fuel and an electric spark lights the mixture. The burning gases expand and blast out through the nozzle, at the back of the engine. As the jets of gas shoot backward, the engine and the aircraft are thrust forward.
http://www.ueet.nasa.gov/StudentSite/images/engines/engineanimated.GIF
The image below shows how the air flows through the engine. The air goes through the core of the engine as well as around the core. This causes some of the air to be very hot and some to be cooler. The cooler air then mixes with the hot air at the engine exit area.





This is a picture of how the air flows through an engine

What is Thrust?

Thrust is the forward force that pushes the engine and, therefore, the airplane forward. Sir Isaac Newton discovered that for "every action there is an equal and opposite reaction." An engine uses this principle. The engine takes in a large volume of air. The air is heated and compressed and slowed down. The air is forced through many spinning blades. By mixing this air with jet fuel, the temperature of the air can be as high as three thousand degrees. The power of the air is used to turn the turbine. Finally, when the air leaves, it pushes backward out of the engine. This causes the plane to move forward.

Parts of a Jet Engine
http://www.ueet.nasa.gov/StudentSite/images/engines/engpartsclr.gif


Fan - The fan is the first component in a turbofan. The large spinning fan sucks in large quantities of air. Most blades of the fan are made of titanium. It then speeds this air up and splits it into two parts. One part continues through the "core" or center of the engine, where it is acted upon by the other engine components.

The second part "bypasses" the core of the engine. It goes through a duct that surrounds the core to the back of the engine where it produces much of the force that propels the airplane forward. This cooler air helps to quiet the engine as well as adding thrust to the engine.

Compressor - The compressor is the first component in the engine core. The compressor is made up of fans with many blades and attached to a shaft. The compressor squeezes the air that enters it into progressively smaller areas, resulting in an increase in the air pressure. This results in an increase in the energy potential of the air. The squashed air is forced into the combustion chamber.

Combustor - In the combustor the air is mixed with fuel and then ignited. There are as many as 20 nozzles to spray fuel into the airstream. The mixture of air and fuel catches fire. This provides a high temperature, high-energy airflow. The fuel burns with the oxygen in the compressed air, producing hot expanding gases. The inside of the combustor is often made of ceramic materials to provide a heat-resistant chamber. The heat can reach 2700°.

Turbine - The high-energy airflow coming out of the combustor goes into the turbine, causing the turbine blades to rotate. The turbines are linked by a shaft to turn the blades in the compressor and to spin the intake fan at the front. This rotation takes some energy from the high-energy flow that is used to drive the fan and the compressor. The gases produced in the combustion chamber move through the turbine and spin its blades. The turbines of the jet spin around thousands of times. They are fixed on shafts which have several sets of ball-bearing in between them.

Nozzle - The nozzle is the exhaust duct of the engine. This is the engine part which actually produces the thrust for the plane. The energy depleted airflow that passed the turbine, in addition to the colder air that bypassed the engine core, produces a force when exiting the nozzle that acts to propel the engine, and therefore the airplane, forward. The combination of the hot air and cold air are expelled and produce an exhaust, which causes a forward thrust. The nozzle may be preceded by a mixer, which combines the high temperature air coming from the engine core with the lower temperature air that was bypassed in the fan. The mixer helps to make the engine quieter.

The First Jet Engine - A Short History of Early Engines

Sir Isaac Newton in the 18th century was the first to theorize that a rearward-channeled explosion could propel a machine forward at a great rate of speed. This theory was based on his third law of motion. As the hot air blasts backwards through the nozzle the plane moves forward.

Henri Giffard built an airship which was powered by the first aircraft engine, a three-horse power steam engine. It was very heavy, too heavy to fly.

In 1874, Felix de Temple, built a monoplane that flew just a short hop down a hill with the help of a coal fired steam engine.

Otto Daimler, in the late 1800's invented the first gasoline engine.

In 1894, American Hiram Maxim tried to power his triple biplane with two coal fired steam engines. It only flew for a few seconds.

The early steam engines were powered by heated coal and were generally much too heavy for flight.

American Samuel Langley made a model airplanes that were powered by steam engines. In 1896, he was successful in flying an unmanned airplane with a steam-powered engine, called the Aerodrome. It flew about 1 mile before it ran out of steam. He then tried to build a full sized plane, the Aerodrome A, with a gas powered engine. In 1903, it crashed immediately after being launched from a house boat.

In 1903, the Wright Brothers flew, The Flyer, with a 12 horse power gas powered engine.

From 1903, the year of the Wright Brothers first flight, to the late 1930s the gas powered reciprocating internal-combustion engine with a propeller was the sole means used to propel aircraft.

It was Frank Whittle, a British pilot, who designed the first turbo jet engine in 1930. The first Whittle engine successfully flew in April, 1937. This engine featured a multistage compressor, and a combustion chamber, a single stage turbine and a nozzle.

The first jet airplane to successfully use this type of engine was the German Heinkel He 178. It was the world's first turbojet powered flight. General Electric for the US Army Air Force built the first American jet plane. It was the XP-59A experimental aircraft.

Types of Jet Engines


Turbojets
http://www.ueet.nasa.gov/StudentSite/images/engines/engpartsclr.gif
The basic idea of the turbojet engine is simple. Air taken in from an opening in the front of the engine is compressed to 3 to 12 times its original pressure in compressor. Fuel is added to the air and burned in a combustion chamber to raise the temperature of the fluid mixture to about 1,100°F to 1,300° F. The resulting hot air is passed through a turbine, which drives the compressor. If the turbine and compressor are efficient, the pressure at the turbine discharge will be nearly twice the atmospheric pressure, and this excess pressure is sent to the nozzle to produce a high-velocity stream of gas which produces a thrust. Substantial increases in thrust can be obtained by employing an afterburner. It is a second combustion chamber positioned after the turbine and before the nozzle. The afterburner increases the temperature of the gas ahead of the nozzle. The result of this increase in temperature is an increase of about 40 percent in thrust at takeoff and a much larger percentage at high speeds once the plane is in the air.

The turbojet engine is a reaction engine. In a reaction engine, expanding gases push hard against the front of the engine. The turbojet sucks in air and compresses or squeezes it. The gases flow through the turbine and make it spin. These gases bounce back and shoot out of the rear of the exhaust, pushing the plane forward.



Picture of Turbojet Engine

Turboprops
http://www.ueet.nasa.gov/StudentSite/images/engines/turbojet.gif
A turboprop engine is a jet engine attached to a propeller. The turbine at the back is turned by the hot gases, and this turns a shaft that drives the propeller. Some small airliners and transport aircraft are powered by turboprops.

Like the turbojet, the turboprop engine consists of a compressor, combustion chamber, and turbine, the air and gas pressure is used to run the turbine, which then creates power to drive the compressor. Compared with a turbojet engine, the turboprop has better propulsion efficiency at flight speeds below about 500 miles per hour. Modern turboprop engines are equipped with propellers that have a smaller diameter but a larger number of blades for efficient operation at much higher flight speeds. To accommodate the higher flight speeds, the blades are scimitar-shaped with swept-back leading edges at the blade tips. Engines featuring such propellers are called propfans.



Picture of turboprop engine

Turbofans
http://www.ueet.nasa.gov/StudentSite/images/engines/turbofan.gif
A turbofan engine has a large fan at the front, which sucks in air. Most of the air flows around the outside of the engine, making it quieter and giving more thrust at low speeds. Most of today's airliners are powered by turbofans. In a turbojet all the air entering the intake passes through the gas generator, which is composed of the compressor, combustion chamber, and turbine. In a turbofan engine only a portion of the incoming air goes into the combustion chamber. The remainder passes through a fan, or low-pressure compressor, and is ejected directly as a "cold" jet or mixed with the gas-generator exhaust to produce a "hot" jet. The objective of this sort of bypass system is to increase thrust without increasing fuel consumption. It achieves this by increasing the total air-mass flow and reducing the velocity within the same total energy supply.



Picture of Turbofan Engine

Turboshafts
http://www.ueet.nasa.gov/StudentSite/images/engines/turboshaft.gif
This is another form of gas-turbine engine that operates much like a turboprop system. It does not drive a propellor. Instead, it provides power for a helicopter rotor. The turboshaft engine is designed so that the speed of the helicopter rotor is independent of the rotating speed of the gas generator. This permits the rotor speed to be kept constant even when the speed of the generator is varied to modulate the amount of power produced.





Picture of Turboshaft Engine

Ramjets
http://www.ueet.nasa.gov/StudentSite/images/engines/RAMJET.GIF
The most simple jet engine has no moving parts. The speed of the jet "rams" or forces air into the engine. It is essentially a turbojet in which rotating machinery has been omitted. Its application is restricted by the fact that its compression ratio depends wholly on forward speed. The ramjet develops no static thrust and very little thrust in general below the speed of sound. As a consequence, a ramjet vehicle requires some form of assisted takeoff, such as another aircraft. It has been used primarily in guided-missile systems. Space vehicles use this type of jet.



Picture of Ramjet Engine


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## سامح الفيومى (29 مايو 2011)

الصور




صورة للمحرك وخطوات الإحتراق وتوليد الدفع


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## سامح الفيومى (29 مايو 2011)

صورة لإجزاء المحرك


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## سامح الفيومى (29 مايو 2011)

المحرك التربو جيب


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## سامح الفيومى (29 مايو 2011)

المحرك التربو بروب
http://www.ueet.nasa.gov/StudentSite/images/engines/Turbopro.gif


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## سامح الفيومى (29 مايو 2011)

المحرك التربو فان
http://www.ueet.nasa.gov/StudentSite/images/engines/turbofan.gif


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## سامح الفيومى (29 مايو 2011)

المحرك التربو فان


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## سامح الفيومى (29 مايو 2011)

*المحرك التربو شافت*


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## سامح الفيومى (29 مايو 2011)

*المحرك الرام جيت*


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## سامح الفيومى (29 مايو 2011)

*حركة الهواء داخل المحرك*


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## سامح الفيومى (29 مايو 2011)

*شرح التربو بروب مع الصور*







o move an airplane through the air, thrust is generated with some kind of propulsion system. Many low speed transport aircraft and small commuter aircraft use turboprop propulsion. On this page we will discuss some of the fundamentals of turboprop engines. The turboprop uses a gas turbine core to turn a propeller. Propellers develop thrust by moving a large mass of air through a small change in velocity. Propellers are very efficient and can use nearly any kind of engine to turn the prop. General aviation aircraft use an internal combustion engine to turn the propeller. In the turboprop, a gas turbine core is used. How does a turboprop engine work?

There are two main parts to a turboprop propulsion system, the core engine and the propeller. The core is very similar to a basic turbojet having a compressor, burner, and turbine. However, at the exit of the main turbine the hot exhaust gas is passed through an additional turbine, shown in green on the schematic, before entering the nozzle. Unlike a basic turbojet, most of the energy of the exhaust is used to turn this additional turbine. The turbine is attached to an additional drive shaft which passes through the core shaft and is connected to a gear box. The gear box is then connected to a propeller that produces most of the thrust. The exhaust velocity of the core is low and contributes little thrust because most of the energy of the core exhaust has gone into turning the drive shaft.

Turning to the math at the bottom of the slide, the thrust of a turboprop is the sum of the thrust of the propeller plus the thrust of the core. We can use our basic thrust equation on the propeller and core to obtain the thrust equation for the turboprop. We denote the free stream conditions by the subscript "0", the conditions at the exit of the propeller by "1", the exit of the core by "e", and the entrance to the core by "c". The mass flow rate is given by m dot and the velocity of the flows by V. The basic thrust equation then becomes:

F = (m dot)0 * V1 - (m dot)0 * V0 + (m dot)e * Ve - (m dot)c * V1

As we have noted above, the mass flow rate through the propeller (m dot)0 is much greater than the mass flow through the core engine (m dot)c. And we have also noted that the exhaust velocity of the core Ve is low and almost equal to the velocity into the core V1. The mass flow rate exiting the core (m dot)e is almost equal to the mass into the core (m dot)c. Mathematicians use the symbol "~" for "almost equals." Collecting this information, we can simplify our basic thrust equation:

F = (m dot)0 * (V1 -V0) + (m dot)e * (Ve - V1)

The first term of this equation is large compared to the second term. Comparing with the pure propeller theory, the thrust is equal to the mass flow through the propeller times the velocity change across the propeller plus a smaller amount of thrust from the core engine.

Because propellers become less efficient as the speed of the aircraft increases, turboprops are used only for low speed aircraft, like cargo planes. High speed transports usually use high bypass turbofans because of the high fuel efficiency and high speed capability of turbofans. A variation of the turboprop engine is the turboshaft engine. In a turboshaft engine, the gear box is not connected to a propeller but to some other drive device. Turboshaft engines are used in many helicopters, as well as tanks, boats, and even race cars in the late 1960's.


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## أحمد_وجيه (29 مايو 2011)

المشاركة 7 تربو فان وليس تربو جيت


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## سامح الفيومى (29 مايو 2011)

*تصحيح للمعلومة*



سامح الفيومى قال:


> المحرك التربو جيب



المحرك المعروض بالصورة فعلا تربو فان وليس تربو جيت
سامحوني
ولكن أردت فقط توضيح اجزاء المحرك التربو عامة


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## amna25 (5 يونيو 2011)

الف الف شكر مهندس سامح الله يوفقك ويسو امورك فرجت همي الله يفرج همك ...


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## حمدان الرشيدي (10 أغسطس 2011)

مشكوووووووووووووووور جزااااااااااااااااك الله خير
يعطيك العافية


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## م_حيدر سامي علم (11 أغسطس 2011)

موضع مثمر


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