{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "stirling-slotted-regenerator-liner",
 "name": "Slotted heater, regenerator and cooler liner for a 2 in hot spool (Ø48.00 / Ø40.00)",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How do I put a real heater, regenerator and cooler inside a single tri-clamp hot tube?",
 "tags": [
  "liner",
  "heater",
  "regenerator",
  "cooler",
  "heat exchanger",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "stirling heater liner",
  "slotted heat exchanger stirling",
  "annular regenerator liner",
  "stirling cooler slots"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/stirling-slotted-regenerator-liner/",
 "sheet_txt": "https://xemstudio.com/objects/stirling-slotted-regenerator-liner/sheet.txt",
 "sheet": {
  "basis": "Design values; slot heat transfer and friction from the laminar rectangular-duct values (Shah & London) and the cycle model on the engine pages",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The displacer runs in the liner's Ø40.00 bore. The gas does not go round the displacer: it goes out through the liner, along 120 slots 0.5 wide and 3 deep cut in its outside under the flame (the heater), through the annular screen stack on its Ø42 neck (the regenerator), along the same slots under the water jacket (the cooler) and in through 16 ports at the cold end.",
   "The slots' fin tips are Ø48.00, a press fit in the finished bore, so the heat crosses from the spool wall into the fins. Heater 50 mm, regenerator 40 mm, cooler 45 mm.",
   "Slot gas volume: heater 9.0 mL, cooler 8.1 mL. Wetted area: about 42 cm² in each of heater and cooler, against about 75 cm² of plain bore.",
   "Fitting: the screen stack goes on the neck first, then the liner is pressed (or shrunk) into the hot spool until its feet touch the floor; the cold end then sits 1.95 mm inside the face, where the Type B gasket's lip holds it."
  ],
  "table": {
   "columns": [
    "zone",
    "z from the spool face",
    "size"
   ],
   "rows": [
    [
     "cold ring",
     "1.95–5",
     "Ø48.00 (slide)"
    ],
    [
     "plenum + ports",
     "5–9",
     "Ø44, 16 × Ø3 at z 7"
    ],
    [
     "cooler slots",
     "9–54",
     "120 × 0.5 × 3, tips Ø48.00"
    ],
    [
     "regenerator neck",
     "54–94",
     "Ø42.00"
    ],
    [
     "heater slots",
     "94–144",
     "120 × 0.5 × 3, tips Ø48.00"
    ],
    [
     "hot plenum",
     "144–147.4",
     "Ø44"
    ],
    [
     "feet",
     "147.4–149.4",
     "3 × 4 wide"
    ],
    [
     "bore",
     "",
     "Ø40.00 (displacer land: run)"
    ]
   ]
  }
 },
 "sheet_text": "Slotted heater, regenerator and cooler liner for a 2 in hot spool (Ø48.00 / Ø40.00) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/stirling-slotted-regenerator-liner/  (CC BY 4.0)\nBasis: Design values; slot heat transfer and friction from the laminar rectangular-duct values (Shah & London) and the cycle model on the engine pages\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The displacer runs in the liner's Ø40.00 bore. The gas does not go round the displacer: it goes out through the liner, along 120 slots 0.5 wide and 3 deep cut in its outside under the flame (the heater), through the annular screen stack on its Ø42 neck (the regenerator), along the same slots under the water jacket (the cooler) and in through 16 ports at the cold end.\n- The slots' fin tips are Ø48.00, a press fit in the finished bore, so the heat crosses from the spool wall into the fins. Heater 50 mm, regenerator 40 mm, cooler 45 mm.\n- Slot gas volume: heater 9.0 mL, cooler 8.1 mL. Wetted area: about 42 cm² in each of heater and cooler, against about 75 cm² of plain bore.\n- Fitting: the screen stack goes on the neck first, then the liner is pressed (or shrunk) into the hot spool until its feet touch the floor; the cold end then sits 1.95 mm inside the face, where the Type B gasket's lip holds it.\n\nzone  z from the spool face  size\ncold ring  1.95–5  Ø48.00 (slide)\nplenum + ports  5–9  Ø44, 16 × Ø3 at z 7\ncooler slots  9–54  120 × 0.5 × 3, tips Ø48.00\nregenerator neck  54–94  Ø42.00\nheater slots  94–144  120 × 0.5 × 3, tips Ø48.00\nhot plenum  144–147.4  Ø44\nfeet  147.4–149.4  3 × 4 wide\nbore    Ø40.00 (displacer land: run)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Academic Press (R. K. Shah, A. L. London): Laminar Flow Forced Convection in Ducts (1978): fRe of rectangular ducts — book — book; correlation cited [verify license at link] — https://doi.org/10.1016/C2013-0-06152-X\n- Ohio University (I. Urieli): Stirling cycle machine analysis (after Urieli & Berchowitz, Stirling Cycle Engine Analysis, 1984): Schmidt and simple analyses, wire-screen regenerator friction fr = 54 + 1.43 Re^0.78 and St = 0.46 Re^−0.4 / Pr — web — university course pages [verify license at link] — https://www.ohio.edu/mechanical/stirling/\n- NASA (W. R. Martini): Stirling Engine Design Manual, 2nd edition, NASA CR-168088 (1983): decoupled second-order losses (shuttle, conduction, flow friction, regenerator) — PDF — US government report — https://ntrs.nasa.gov/citations/19830022057\n- Cambridge University Press (J. R. Senft): Mechanical Efficiency of Heat Engines (2007): shaft work = E·W − (1/E − E)·W_forced — book — book; formula cited [verify license at link] — https://doi.org/10.1017/CBO9780511546105\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/stirling-slotted-regenerator-liner/index.json\nAPI: https://xemstudio.com/api/geometry?object=stirling-slotted-regenerator-liner\n",
 "sources": [
  {
   "publisher": "Academic Press (R. K. Shah, A. L. London)",
   "title": "Laminar Flow Forced Convection in Ducts (1978): fRe of rectangular ducts",
   "url": "https://doi.org/10.1016/C2013-0-06152-X",
   "formats": [
    "book"
   ],
   "license": "book; correlation cited",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Ohio University (I. Urieli)",
   "title": "Stirling cycle machine analysis (after Urieli & Berchowitz, Stirling Cycle Engine Analysis, 1984): Schmidt and simple analyses, wire-screen regenerator friction fr = 54 + 1.43 Re^0.78 and St = 0.46 Re^−0.4 / Pr",
   "url": "https://www.ohio.edu/mechanical/stirling/",
   "formats": [
    "web"
   ],
   "license": "university course pages",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "NASA (W. R. Martini)",
   "title": "Stirling Engine Design Manual, 2nd edition, NASA CR-168088 (1983): decoupled second-order losses (shuttle, conduction, flow friction, regenerator)",
   "url": "https://ntrs.nasa.gov/citations/19830022057",
   "formats": [
    "PDF"
   ],
   "license": "US government report",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Cambridge University Press (J. R. Senft)",
   "title": "Mechanical Efficiency of Heat Engines (2007): shaft work = E·W − (1/E − E)·W_forced",
   "url": "https://doi.org/10.1017/CBO9780511546105",
   "formats": [
    "book"
   ],
   "license": "book; formula cited",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "tri-clamp-closed-hot-spool-bored",
  "stirling-annular-screen-stack",
  "stirling-clearance-seal-displacer",
  "list-tri-clamp-horizontal-gamma",
  "list-tri-clamp-charged-beta"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [
  {
   "feature": "cold ring OD",
   "exact": "Ø48.00, z 1.95–5",
   "mates": "hot-spool finished bore",
   "fit": "slide",
   "files": "all"
  },
  {
   "feature": "fin tips",
   "exact": "Ø48.00, 120 slots 0.5 wide, z 9–54 and 94–144",
   "mates": "hot-spool finished bore (the heat path)",
   "fit": "press",
   "files": "all"
  },
  {
   "feature": "regenerator neck",
   "exact": "Ø42.00 × 40",
   "mates": "screen stack bore",
   "fit": "slide",
   "files": "all"
  },
  {
   "feature": "bore",
   "exact": "Ø40.00 × 145.45",
   "mates": "displacer land Ø40.00",
   "fit": "run",
   "files": "all"
  },
  {
   "feature": "cold end face",
   "exact": "annulus Ø40–Ø48 at z 1.95",
   "mates": "Type B gasket lip (holds the liner)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "feet",
   "exact": "3 × 4 wide, to z 149.4",
   "mates": "hot-spool floor",
   "fit": "designed",
   "files": "all"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "Why slots and not the plain annular gap?",
   "a": "A plain 0.5 mm gap on a Ø48 bore has about a fifth of the wetted area; with air at a charge the cooler then runs far above the water temperature."
  },
  {
   "q": "What does the press fit do?",
   "a": "It is the heat path from the spool wall into the fins. The engine numbers assume 5000 W/(m²·K) at the fin tips."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "liner-2in-slotted-48-40",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/stirling-slotted-regenerator-liner/liner-2in-slotted-48-40.step",
   "stl": "https://xemstudio.com/files/hardware/stirling-slotted-regenerator-liner/liner-2in-slotted-48-40.stl",
   "note": "slotted heater / regenerator / cooler liner for the Ø48.00 hot spool: bore Ø40.00 × 145.45; cold ring Ø48.00; plenum Ø44 with 16 × Ø3 ports; cooler and heater: 120 slots 0.5 wide from the Ø48.00 tips to the Ø42.00 root (45 and 50 long); regenerator neck Ø42.00 × 40; three 4 mm feet"
  }
 ],
 "markdown": "https://xemstudio.com/objects/stirling-slotted-regenerator-liner/index.md"
}