The Ceiling Jet In Fires

Abstract

The steady fire-produced ceiling jet in an open ended corridor is examined with a simplified "top hat" theory. At a corridor open end, the hot fluid accelerates upward producing a Richardson Number equal to I for tranquil flow as the flow control. Friction satisfies this condition by upstream waves with a hydraulic jump, if necessary. Entrainment has qualitatively the same result, but with quantitative differences. Heat transfer at low friction causes the Richardson Number and depth to rise. The manner of adjustment to Ri = I at an open end needs further study.