Telic Engineering / Field notes / Week 47

DLE mapping explained

Week 47Remco Petersen

Sheet 47

Field note, first posted on LinkedIn.

A narrow window. Mapping finds it. Cross-section of a triple annular lean premix DLE combustor: premixer module through the casing with three cups A, B and C feeding three flame zones between the inner and outer liner, HPT nozzle at the exit. Next to it the flame temperature windows of the five LM6000 burner modes B, BC/2, BC, AB and ABC, each with a hot edge and a lean edge, and the schedule running through them: bleed closes across each window, at the hot zero-bleed corner the control stages up and flame temperature drops into the next mode. Six numbered points. FROM COMPRESSOR A B C A B C DOME HPT PREMIXER MODULE POWER FLAME TEMPERATURE LM6000 BURNER MODES · SHAPE ONLY EACH WINDOW: MAX BLEED LEFT, ZERO BLEED RIGHT B BC/2 BC AB ABC HOT EDGE · NOx / DYNAMICS LEAN EDGE · CO / UHC STAGE UP MAX BLEED ZERO BLEED 01THREE FLAME RINGSA outer, B pilot, C inner 02BURNER MODESB always lit, A and C staged in 03LEAN EDGECO and UHC, then blowout 04HOT EDGENOx or dynamics, first one wins 05WINDOW PER MODEeach mode has its own 06THE SCHEDULEbleed holds it, stage up at the corner

A DLE engine runs in a narrow window. Mapping is how you find it. And there is one per burner mode.

  1. 1.Three flame rings. Outer A, pilot B, inner C. Only the pilot ring is always fuelled.
  2. 2.Burner modes. Rings are staged in as power goes up. On an LM6000: B, BC/2, BC, AB, ABC.
  3. 3.Lean limit. Too cold: CO and unburnt hydrocarbons climb, then flame-out.
  4. 4.Hot limit. Too hot: NOx climbs and combustion dynamics rise. Whichever comes first sets the edge.
  5. 5.A window per mode. Each mode has its own window, and it moves with power.
  6. 6.The schedule. Set inside every window with margin. Bleed walks the engine across it, and at the corner of the window the control stages up.

How do you prepare a unit for mapping? What do you check first?

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Mapping after an engine change? I take care of the controls side, together with an experienced DLE mapper. Send me a message.

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Remco Petersen
Telic Engineering B.V.
Markenplein 24, 1011 MV Amsterdam
The Netherlands
remco.petersen@telic-engineering.nl
+31 6 51345316
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