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Thermoacoustic finned hot head: one-piece closed hot end for 2 in tri-clamp
How do I close the hot end of a tri-clamp thermoacoustic engine without a gasket in the flame? · Hardware · basis: ISO 2852 face and 20° back exactly as the tri-clamp ferrule on this site (gen_hardware.tc_ferrule); ASME BPE 2 in tube; inside length from the standing-wave layout in tools/gen_ta_family.py
Long Earth Society build part. The one-piece hot end of my propane standing-wave engines. The engines
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 5 in table
Notes
- A closed-end tube with a clamp face: the whole hot end is one piece, so the only joint is at the face, 133.35 mm from the flame end, where the water jacket keeps it cool. The clamp face, recess and back cone are the ferrule's, so a standard clamp and Type B gasket join it to any 2 in fitting.
- Inside, from the closed end: a 60 mm hot cavity (liner), hot exchanger, 40 mm honeycomb stack, cold exchanger, 8.4 spacer to the gasket lip. Outside, 16 radial fins over the last 77.35 mm take the torch's heat into the hot cavity and the hot exchanger.
- Hot cavity: the model puts the onset at about 271 °C (half-wave) and 209 °C (quarter-wave) with the exchanger 60 mm off the end, against about 680 °C (half-wave) and over 1000 °C (quarter-wave) with it on the end, where the gas hardly moves.
- Fits: the bore takes the exchangers, stack and liner as a slide fit; the face is a clamp face.
Sizes
| feature | value |
|---|---|
| face | ISO 2852, 2 in (Ø64 flange) |
| tube | Ø50.8 × 1.65 |
| inside length | 130.35 |
| overall | 133.35 |
| fins | 16 × 1.6 thick, to Ø76, z 56–133.35 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| head face | ISO 2852 (land Ø56.5–Ø64, rim 2.85, 1.6 recess, 20° back) | standard clamp + Type B gasket | clamp | all |
| bore | Ø47.5 × 130.35 to the closed end | heat exchangers, honeycomb stack, bore spacers | slide | all |
| fins | 16 × 1.6 to Ø76, z 56–133.35 | torch flame (no contact) | designed | all |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| G. W. Swift (LANL / Acoustical Society of America) | Thermoacoustics: A Unifying Perspective for Some Engines and Refrigerators (Rott's equations, screen relations, DeltaEC) | web, software | LANL verify |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| ta-finned-head-2in | 2 in finned hot head: ISO 2852 face (as the ferrule), tube Ø50.8 × 1.65 wall, inside floor 130.35 from the face, closed end 3 thick (133.35 overall); 16 radial fins 1.6 thick to r 38 from 56 to the end | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=thermoacoustic-finned-hot-head
How it fits
In these build lists
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Questions
Why not a cap and a hot gasket?
A gasket in the flame is the first thing to fail; here the joint is 133.35 mm above the flame, next to the water jacket.
Why is the stack not on the closed end?
At a closed end the gas barely moves, so a stack there does little; moving it 60 mm in lets the gas oscillate through it.