噴氣推進/噴氣發動機型別
< 噴氣推進
衝壓發動機使用開放的 布雷頓迴圈。不使用旋轉機械，壓縮是由進氣道和擴散器實現的。因此，它們需要速度來壓縮足夠的空氣，以便實現良好的效率。衝壓發動機在 亞音速 下效率低下，並且它們的效率在超音速下提高。
燃料被注入壓縮空氣中，並使用火焰穩定器燃燒，以穩定湍流火焰，如加力燃燒室。
在 高超音速 下，壓縮和解離過程使完全擴散變得不可取，並且正在研究超燃燃燒。一個 超燃衝壓發動機 將空氣減速至低超音速，然後燃燒高火焰速度燃料（如氫或甲烷），以嘗試獲得淨推力。
當速度增加時，氣流的總溫度會升高到超過燃燒產物的解離溫度。如果氣流被擴散到亞音速，這將阻止有效燃燒。為了解決這個問題，使用高傳播速度的燃料（如氫），同時將進氣空氣擴散到超音速，而不會使氣流的溫度大幅上升。挑戰變成獲得穩定的火焰鋒面和淨推力。
渦噴發動機增加了由渦輪驅動的旋轉壓縮機。這使得壓縮超過進氣道的停滯壓力，並在較低速度下提高了相對於衝壓發動機的效率。熱空氣離開渦輪後被噴嘴加速並排出。加力燃燒室可用於增加推力。
一個包絡的葉扇允許更大的空氣質量被一個包絡的葉扇移動，該葉扇的流動繞過核心。葉扇相對於核心的相對尺寸由 旁通比 確定。
下圖顯示了典型的雙軸高旁通渦扇發動機的佈局。
渦扇發動機中渦扇旁通質量流量與發動機核心質量流量的比率。
顧名思義，這是繞過發動機核心並流過發動機外部並透過噴嘴排出的空氣的比率。在現代高旁通比發動機中，旁通比可以高達 85%。增加葉扇的尺寸和旁通比會導致重量增加。無導流風扇或 螺旋槳風扇 的重量增加較小，但噪音在西方一直不可接受。
由於葉扇的直徑遠大於渦輪，因此它必須以低得多的轉速執行。傳統上，這是透過多個渦輪級來實現的。然而，這使得渦輪系統不必要地複雜，因此人們試圖使用齒輪箱來減少所需的渦輪級數量。到目前為止，功率要求尚未應用於更大的渦扇發動機，但公司仍在嘗試。
示例：Honeywell_ALF_502 用於 BAe 146。
帶齒輪箱和螺旋槳的渦軸發動機。
進氣道、壓縮機、燃燒室和驅動軸的渦輪。用於直升機、輔助動力裝置，以及地面應用，如坦克、船舶、發電。
使用脈衝爆轟來關閉進氣道，而無需初級壓縮。進氣道關閉可以是動態的，也可以使用機械閥（如 簧片閥）。
TYPES OF PROPULSION SYSTEMS (BASIC EXPLANATION LISTING)
我是一名 FAA 認證的噴氣發動機、活塞發動機和機身機械師，並且精通應用物理學和系統設計。以下是我對噴氣發動機本身，以及渦輪發動機和所有其他推進動力裝置的分類方式
1.) Turbine Propulsion:
A.) Turbojets Engines - No Bypass Cold Airflow Duct and large front Fan, just compressor-turbine spool(s) core.
B.) Turbofan Engines - Large Fan in ahead of compressor-turbine spool(s) core with By-Pass Cold Airflow Duct around
engine body and compressor-turbine spool(s) core.
2.) 渦輪扭矩
A.) Turboshaft Engines - More Turbine Stages w/ Free Turbine to Gear Reduced
Transmission.
B.) Turrboprop Engines - Same as Turboshaft Engine except Fuel Control Unit
is linked to Blade Pitch System to prevent Windmilling of Propeller and
RPM on a Turboprop Engine is controlled by Blade Pitch Control.
3.) Non-Turbine Propulsion Powerplants:
A.) Ramjet - Hollow convergent venturi tube, lit off when enough forward airspeed is
present to provide the compression needed to light it off. Higher in efficiency and
thrust than Propulsion Turbine Powerplants and is dependent on the ability of the
fuel injection system pressure and fuel volume delivery limits. Ramjets are limited
to speeds below where the Nitrogen and Oxygen in the air do not compress to such
enormous pressures as to where the Oxygen and Nitrogen merge as one killing
combustion. (Note: Air is 78% Nitrogen, 21% Oxygen & 1% various Inert
Gases).
B.) Scramjet - Supersonic Scramjet or "scramjet". These propulsion powerplants are
ramjets rated for much higher speeds from supersonic to into hypersonic speeds
(more than 4000 MHP). The only limitation is what any ramjet needs to overcome:
The merger of Oxygen and Nitrogen in the Air under enormous compression,
when not controlled will merge the Oxygen and Nitrogen as one and kill
combustion.
C.) Pulsejet - Hollow convergent venturi tube or any type of differential diameter dual
channel which doesn't need to be routed across in a linear manner, but in the same
way hydraulic and pneumatic systems can route the master and actuator cylinders in
series, any which way in terms of orientation. There are glass jars and dual plumbing
pipes with differential diameters which can be made into pulse jets. The typical
aviation-type Pulse Jet is a convergent venturi channel with spring-loaded shutters on
the intake. During the combustion cycle, a vacuum develops in the aft exhaust
section of the venturi causing the spring-loaded-opened shutters to pass airflow during
combustion, until the vacuum increases more than the spring-loaded-open shutters
can handle causing them to close. This allows a sealing-bias on the intake side as to
maximize thrust in the aft rear section. But only for a limited dwell-time pulse cycle as
to where combustion ceases and allows the shutters to open again to repeat the
process. The aviation-type Pulse Jets run at a frequency around 250 to 600 PPS.
As the frequency increases, the Pulse Jet comes online as running into the full thrust
rating as fuel delivery increases to maximum limits. Aviation-grade Pulse Jets may
utilize Heat-of-Compression on high compression Pulse Jet designs running on
kerosene (same as "jet fuel") which allow the Pulse Jet to stay lit without additional
spark plug or glow plug requirements after being lit off, which time the shutters to the
fuel injection system. Or gasoline-models using shutter position to spark can be used
if the compression is lower than needed for allowing a Heat-of-Compression
combustion cycle to be utilized. Plumbing pipes of different diameters connected 180
degrees to each other on a 180 degree bend and can be turned into Pulse Jets too.
This by using a fuel source in the smaller diameter pipe with spark plug and when it
lights off, spark isn't needed anymore, because the compression rises high enough to
keep the Pulse Jet lit. The 180 degree bend between the two different diameter pipes
allow a high pulse on/off frequency to develop between combustion and fuel flow dwell
when the combustion ceases. Something in the range of 1200 cycles per second.
They're noisy for sure, but keep lit on their own. Also a glass jar with a cover at the
top and small hole at the center with a little bit of gasoline in the bottom, carefully
heated on a stove will light off at the top where the hole is and will light off around
1200 cycles per second as a Pulse Jet. Just be careful on adjusting the heat when
using a glass jar.
D.) Rocket Propulsion - These Propulsion Powerplants utilize a tapering convergent
channel within their airframe fuselage section in which a fuel which carries its own
oxygen along with combustible compounds ignite. Escaping through the tapered
convergent channel into thrust. Typical Rocket Fuels are both liquid and solid Oxy-
Hydro Fuels which are Oxygen and Hydrogen mixed together and ignited. Other
Rocket Fuels include Hydrogen Peroxide mixed with a catalyst in separate reservoirs
injected into the taper convergent thrust channel at the correct ratios to support
combustion. This also goes for the Space Shuttle as well, using liquid Oxygen and
Hydrogen in separate reservoirs mixed with emulsified aluminum as to increase thrust
output. Rocket Propulsion speeds are rated to over 30,000 MHP and are more
practical for defense, high altitude weather/surveillance and space programs than
passenger flight, at least for now this is the case.
E.) Missile Propulsion - Missile Propulsion is similar to Rocket Propulsion, except far
more airframe system guidance is involved in the likes of airplanes flying on GPS or
Radar-Guided systems which control Missile Airframe Flight Control Systems. This for
pin-point guidance, steering and targeting/evasive actions to specific target and
collision/avoidance from specific threats. Many missile designs either incorporate
Rocket Propulsion in the same manner as Rockets or use small turbojet engines
within their fuselage. More advanced missile designs are starting to use Ram Jets
along with an initial Rocket Propulsion light-off to get them up to speed. When they
reach a specific airspeed usually around 500 MHP, the Ram Jet will kick in using Oxy-
Hydro fuel to keep them lit and can increase in speeds to around 2,200 MHP while
also fly at low altitudes. Many of these types of missile designs also incorporate
Microwave & Doppler Radar Tracking & Cancellation Systems. So they can't be
tracked by most any type of Radar, even more advanced Radar Systems which
track flying objects by their airflow pattern converted into a visual profile. Such
missiles have been pioneered by Russia & India, such as the Moskit from Russia
and the Bramos from India.
F.) Air Pressure Propulsion - This is none other than a larger diameter accumulator
shaped like a cylinder with an enormous amount of air pressure pre-charged connected
to a powerful air compression with high volume capacity tank. On the other end of this
cylinder is a small diameter pipe which when opened up passing a high amount of air
velocity, by the air pressure being stepped down at the end before the smaller tail pipe
begins causing the air velocity to rise. These types of Propulsion Systems require a
constant pressure to remain at a certain limit within the accumulator cylinder to be
effective for any practical thrust. Experimental applications using this type of
propulsion would also require a large enough accumulator cylinder to provide for
enough constant pressure to stagnate while the air escapes through the small tail pipe
into thrust. [Pressure = Force / Area; Force = Pressure x Area. This is the basic
principle on how hydraulics, pneumatics, firearms, rockets, jet propulsion, piston
engines and aircraft operate by].