{
 "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-annular-screen-stack",
 "name": "Annular regenerator screen stack, Ø48 / Ø42 × 40 (50 mesh × 0.22 mm wire)",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How big should the regenerator screen stack be in a 2 in Stirling engine?",
 "tags": [
  "regenerator",
  "screen",
  "mesh",
  "matrix",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "stirling regenerator mesh size",
  "wire screen regenerator",
  "annular regenerator stack"
 ],
 "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-annular-screen-stack/",
 "sheet_txt": "https://xemstudio.com/objects/stirling-annular-screen-stack/sheet.txt",
 "sheet": {
  "basis": "Porosity of stacked square-weave screens 1 − π m d / 4; friction and heat transfer from the Urieli & Berchowitz screen correlations",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Annular screens punched Ø48.00 outside, Ø42.00 inside, stacked 40 mm deep on the liner's neck: about 91 screens of 50 mesh (per inch) × 0.22 mm wire, porosity 0.660, hydraulic diameter 0.43 mm.",
   "Gas volume in the stack 11.2 mL. In the cycle model its effectiveness is 0.966 on charged air at 600 rpm and 0.980 on helium at 1200 rpm.",
   "Finer screens raise the effectiveness and the pumping loss together; I swept 0.10 to 0.30 mm wire and 0.22 mm was the best shaft power on air and on helium."
  ],
  "table": {
   "columns": [
    "item",
    "value"
   ],
   "rows": [
    [
     "envelope",
     "Ø48.00 / Ø42.00 × 40"
    ],
    [
     "screen",
     "50 mesh × 0.22 wire"
    ],
    [
     "count",
     "≈ 91"
    ],
    [
     "porosity",
     0.66
    ]
   ]
  }
 },
 "sheet_text": "Annular regenerator screen stack, Ø48 / Ø42 × 40 (50 mesh × 0.22 mm wire) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/stirling-annular-screen-stack/  (CC BY 4.0)\nBasis: Porosity of stacked square-weave screens 1 − π m d / 4; friction and heat transfer from the Urieli & Berchowitz screen correlations\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Annular screens punched Ø48.00 outside, Ø42.00 inside, stacked 40 mm deep on the liner's neck: about 91 screens of 50 mesh (per inch) × 0.22 mm wire, porosity 0.660, hydraulic diameter 0.43 mm.\n- Gas volume in the stack 11.2 mL. In the cycle model its effectiveness is 0.966 on charged air at 600 rpm and 0.980 on helium at 1200 rpm.\n- Finer screens raise the effectiveness and the pumping loss together; I swept 0.10 to 0.30 mm wire and 0.22 mm was the best shaft power on air and on helium.\n\nitem  value\nenvelope  Ø48.00 / Ø42.00 × 40\nscreen  50 mesh × 0.22 wire\ncount  ≈ 91\nporosity  0.66\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\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-annular-screen-stack/index.json\nAPI: https://xemstudio.com/api/geometry?object=stirling-annular-screen-stack\n",
 "sources": [
  {
   "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": [
  "stirling-slotted-regenerator-liner",
  "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": "outside",
   "exact": "Ø48.00",
   "mates": "hot-spool finished bore",
   "fit": "slide",
   "files": "all"
  },
  {
   "feature": "inside",
   "exact": "Ø42.00",
   "mates": "liner neck",
   "fit": "slide",
   "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": "Can I use a different screen?",
   "a": "Yes; keep the stack length and the porosity near 0.66 and re-run the numbers."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "screen-stack-48x42x40-50mesh",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/stirling-annular-screen-stack/screen-stack-48x42x40-50mesh.step",
   "stl": "https://xemstudio.com/files/hardware/stirling-annular-screen-stack/screen-stack-48x42x40-50mesh.stl",
   "note": "regenerator screen stack envelope Ø48.00 / Ø42.00 × 40: about 91 annular screens, 50 mesh × 0.22 wire (porosity 0.66)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/stirling-annular-screen-stack/index.md"
}