Skip to main content
26 votes
Accepted

How does a turbofan with afterburner continue to function in extreme humidity and rain?

The air is compressed in the compressor section of the engine and heats up. Hot air is able to hold disproportionally more water in gaseous form than cold air, so all that water will vaporize and ...
Peter Kämpf's user avatar
12 votes

Why would a jet engine use cannular combustors if the annular design is superior?

Single combustor cans are simpler to develop. To get the ignition and combustion process right in an annular combustor is quite a challenge. When the first jet engines were developed, Junkers decided ...
Peter Kämpf's user avatar
12 votes

Function of the compressor in a gas turbine engine

The reason is thermodynamics: without the compressor, the power output of a gas turbine would be exactly zero. It's not about being "more efficient" but about fundamentally being able to ...
Sanchises's user avatar
  • 13.4k
10 votes
Accepted

What is the temperature of the air leaving the combustion chamber of a CFM56-5C?

Quick answer: At the design point considered, which is assumed to be takeoff conditions, a CFM56-5C combustor raises gas temperature to 1360°C (the share of the compressor in this raise is about 600 °...
mins's user avatar
  • 74.7k
8 votes

Can some one please explain to me the purpose of the combustion chamber?

OK, this answer will definitely be trumped by better ones, and Google will serve you better, but until then.... Thrust is basically throwing a mass of stuff in the opposite direction you want to ...
Mackk's user avatar
  • 1,585
8 votes

Function of the compressor in a gas turbine engine

The compressor raises the pressure and temperature at which the fuel is burned, thereby increasing the thermodynamic efficiency of the cycle (Brayton) on which the jet operates. Second, without the ...
niels nielsen's user avatar
8 votes
Accepted

Function of the compressor in a gas turbine engine

You don't. A (sc)ramjet doesn't have a compressor, as the forward velocity of the jet provides the necessary pressure. Most thermal engines do work by expanding a gas. In many cases, this gas expands ...
Lawnmower Man's user avatar
7 votes
Accepted

What is the difference between single and dual annular combustor?

Here's an engine with old combustor cans: Here's a single annular combustor: And in cross section: And now here's a dual annular combustor (DAC) (pic from here) in cross section: See how it's ...
Penguin's user avatar
  • 4,483
6 votes

Why would a jet engine use cannular combustors if the annular design is superior?

The first operational jet engine contract was awarded to GE/Allison as the J35 and was later upgraded to the J47. When I was at tech school for the J47 we were told GE was given the contract because ...
jwzumwalt's user avatar
  • 11.5k
6 votes
Accepted

How is the correct air speed for fuel combustion obtained at the inlet of the combustor?

In general, aircraft jet engines have diffuser section(s), that reduce the velocity of the incoming air before it enters the combustion chamber. Sample velocity profile in jet engine; image from ...
aeroalias's user avatar
  • 100k
6 votes

How is the correct air speed for fuel combustion obtained at the inlet of the combustor?

Combustors usually feature recirculation zones in which the combustion takes place either completely or which at least anchor the flame. This can be done by several designs Sudden jump in cross-...
Chris's user avatar
  • 174
6 votes
Accepted

How is flame stabilisation carried out?

As usual, it is a combination of measures: Flow speed at the start of the combustion chamber is the lowest in the whole engine, in the order of 30 m/s. High fuel pressure and many small fuel injector ...
Peter Kämpf's user avatar
6 votes

Why would a jet engine use cannular combustors if the annular design is superior?

Modern jet engines do not use can or cannular combustors. GE made the switch to annular combustors by at least the J85, which had a first engine to test in the 1950s. The TF39 (1964) engine formed the ...
OSUZorba's user avatar
  • 2,639
5 votes

Why do gases in the combustion chamber only flow one direction to the gas turbine in a jet engine?

I happened upon this question, and thought I could add some information, as I recognized the powerplant right away. This is not another full answer, but only a response to @albin and @PeterKampf as ...
Bronco6363's user avatar
5 votes

What is the absolute velocity change through compressor+burner?

This image that TomMcW posted in the comments is a much better representation of what is going on. First, looking at axial velocity only is only half of the story, through the compressor and ...
OSUZorba's user avatar
  • 2,639
4 votes
Accepted

What is the absolute velocity change through compressor+burner?

The flow enters the compressor at approximately Mach 0.4 to 0.6 in order to ensure a high mass flow with still subsonic compressor blade speeds. Compressing the air allows to reduce flow speed, and ...
Peter Kämpf's user avatar
4 votes
Accepted

Why is the fuel:air ratio of a turbojet engine not around ~1:15 (the stoichiometric ratio)?

Edit: to honor my original answer, I shall keep it as it is. The question was edited so much I think it would have constituted a whole new question. In it's original form, the Q presented jet engine f/...
Jpe61's user avatar
  • 29.1k
4 votes

Function of the compressor in a gas turbine engine

In order for a jet to create thrust, pressure must be created so the difference in pressure from the inside of the engine to the outside air will create a flow of a certain mass at a certain velocity. ...
Robert DiGiovanni's user avatar
4 votes
Accepted

Is there any version of CFM56 with can combustors?

In short It's the flame tube of an individual can of a cannular combustor, a mix between can and annular combustors. The can may come from auxiliary power unit turbine or a JT8D powering older Boeing ...
mins's user avatar
  • 74.7k
3 votes
Accepted

Would a pulsejet/turbine hybrid be efficient?

Some good thinking here but let's start with the basics: Pulse jets require a tuned pipe for adequate compression. The design sends a shockwave back from the exhaust pipe towards the combustion area. ...
Robert DiGiovanni's user avatar
3 votes

How is the correct air speed for fuel combustion obtained at the inlet of the combustor?

How engineers are able to slow air without decompressing it Flow speed is energy, so slowing down the flow will increase its pressure. At subsonic speeds the first part happens already ahead of the ...
Peter Kämpf's user avatar
3 votes

What materials are used to make up a combustion chamber?

If you are asking about combustor liners specifically (as opposed to the hot section in general), the ones I am familiar with are cobalt-based superalloys.
Daniel K's user avatar
  • 5,518
3 votes

Function of the compressor in a gas turbine engine

Would a jet engine need the compressor? All heat engines require a compression step, only in turbomachinery the part involved is called compressor. But other engines also compress a medium as part of ...
Peter Kämpf's user avatar
2 votes

What are the differences between single and double annular combustion chambers?

See this answer for the difference between a SAC and DAC combustor. The EASA type certificate for the CFM56-7 also identifies which engines have the DAC and which have the SAC. The answer depends on ...
Penguin's user avatar
  • 4,483
2 votes

What is the Fuel-Oxygen ratio for a large turbofan at cruise conditions?

I chose the GE90-115B because it is the largest turbofan in terms of thrust. Unfortunately, it was hard to come by specific fuel consumption figures for cruise conditions, maybe because the -115B is a ...
DrZ214's user avatar
  • 17.8k
2 votes

What materials are used to make up a combustion chamber?

This is more of an engineering question than an aviation question, but since some aviators may be interested in knowing exactly what is in those turbines I will answer. There are three main types of ...
Tyler Durden's user avatar
  • 13.3k

Only top scored, non community-wiki answers of a minimum length are eligible