View Factor
The fraction of radiation leaving surface 1 that strikes surface 2 directly, from the standard closed-form relations (Cengel ch.12). Use reciprocity F₂₁ = F₁₂·A₁/A₂ and summation to close any enclosure.
Geometry
Dimensions
Frequently asked
- What is a view factor?
- The fraction of diffuse radiation leaving surface 1 that hits surface 2 directly. It is pure geometry — no temperatures, no emissivities.
- Which enclosures are covered?
- Coaxial parallel disks (Eq. 12-16), sphere centered over a disk, concentric spheres/cylinders/squares, long perpendicular rectangles sharing an edge, long parallel offset rectangles, and triangle ducts from side lengths.
- How do I get the reverse factor?
- Reciprocity: F₂₁ = F₁₂·A₁/A₂. For enclosures, the summation rule F₁₁ + F₁₂ + ... = 1 closes the rest.