# How hot do internal parts of jet engine get?

How hot does a jet engine get? I'm interested in the temperature of the parts, not of the exhaust or combustion. If you took temperature of an engine after a flight across the Pacific Ocean what are temperatures of stationary and movable parts? A car engine block may be 250 degrees Fahrenheit (120°C). I'm thinking of how to modify the basic architecture.

• – Manu H Feb 11 '20 at 8:21

This parameter is called Turbine Inlet Temperature (TIT)

Turbine Inlet Temperature (TIT) is the temperature of the combustion chamber exhaust gases as they enter the turbine unit. The gas temperature is measured by a number of thermocouples mounted in the exhaust stream and is presented on a flight deck gauge in either degrees Fahrenheit or degrees Celcius.

Essentially it's the temperature going out of the combustion chamber, representing the highest temperature the turbine would face.

Here's a figure showing how we are doing recently. So we are at around 1800K now and may reach 2000K soon.

For the temperature of the actual part under cooling, here is the current status of materials: we are at around the 1350K mark and may approach 1400K soon.

• The reason we're talking about "cooled" is because we're routinely exceeding the temperature at which the turbine blades would melt. So, since the question explicitly mentions "parts temperature, not exhaust temperature" this is somewhat of an overestimation. – MSalters Feb 11 '20 at 12:35
• You should have included the graph preceding the one you used since it gives maximum part temperature capacity. – Peter Kämpf Feb 11 '20 at 16:22
• just a heads up - the first link doesn't point to an actual URL – crass_sandwich Feb 11 '20 at 20:18
• @crass_sandwich Fixed. – user3528438 Feb 11 '20 at 20:24
• Impressive use of graphs, but I have never seen a TIT or ITT gauge calibrated in Kelvin. Could you make this more relatable, and use the same UOMs in the question? Also, what engine do these graphs represent? – Michael Hall Feb 11 '20 at 23:17

Depends on the section of the engine in question. The 'hot section' of a jet engine gas core, which consists of the isobaric combustor, high pressure turbine and low pressure turbine, by far, operates at the highest temperatures. On modern, high performance aviation gas turbines, the high pressure turbine inlet temperatures are reaching nearly 3,600° F during full power operation. Exhaust Gas temperatures in the jet pipe just aft of the last low pressure turbine stage are in the neighborhood of 1,000° F. Air exiting the high pressure compressor section will be around 500° F.

A little basic thermodynamics will quickly demonstrate that the hotter you can operate the gas at the beginning of its expansion through the turbine section of the engine, the more efficient the engine will be. This increase in temperature is, of course limited by the material properties of the metals and composites used to manufacture these engine parts. Jet engine turbine sections are usually manufactured from novel nickel-cobalt and titanium superalloys using novel single crystal casting techniques for maxiumum structural strength. In addition, they also make use of compressor bleed air for use as a boundary layer to prevent direct contact between the walls, stator and rotor blades and the high temperature gases.

Compressor exit temperature and turbine inlet temperature are the hottest regions, front and back of combustor respectively. However, it is rare that TIT is directly measured. Most times the inter turbine temperature (ITT - ARP station 4.5) and station 5 (EGT - exit of the low pressure turbine, back of the core stream) are measured and mathematical and thermodynamic models back out what the TIT would be. The cockpit displays EGT, not TIT. But referencing the graph above, the trend is real but it’s not actually measured directly. Too hot back there.