Transient Analysis of Fire-Induced Heat Transfer in Cylindrical Sealed Space
The main objective of the present work is an investigation of the heat transfer induced by the fire in a cylindrical sealed space. The thermal smoke flow geometry characteristics in cylindrical sealed space were discussed, LES and mixture fraction methods were applied to conduct numerical transient analysis. Computed results has validated the smoke flow course in simulation experiments. The study indicates that the heat transfer faster upper the fire source than around it. When the fire source location is near the wall, the smoke layer distributing were not distinct far from the fire source, and the heat transfer faster in transverse than longitudinal direction. Keywords—heat transfer , fire, cylindrical sealed space, numerical simulation.
Buoyant plumes of large-scale pool fires
A series of large-scale pool fire tests were conducted to investigate the variation of plume gas temperature and velocity. Three pool diameters: 1.219 m, 1.737 m and 2.438 m, were selected; four fuels with drastically different heat release rates were employed. In each test, measurements were made of plume gas temperatures and velocities and weight loss of the fuel pool. The measured plume temperature profiles at several elevations were fitted with Gaussian distributions in order to determine plume centerline position and centerline values of gas temperatures and velocities. The plume convective heat flux was then determined from the fitted profiles of plume temperatures and velocities. The plume centerline temperature followed the 2/3 power of the convective heat flux, Qc, and the −5/3 power of the pulme height with respect to the virtual source location, z-zo, down to the level where intermittent flames were found; the centerline gas velocity varied as the 1/3 power of Qc and −1/3 power of z-zo. The virtual source locations were found to be related to the flame heights. For large values of the ratio of flame height versus pool diameter, the distance from the flame tip to the virtual source is proportional to the 2/5 power of the convective heat flux and the virtual source location correlates well with a parameter10 sed for flame correlation. For small flame-height to pool-diameter ratios, in several tests, the virtual source locations were below the pool surface; however, the virtual source moved upward as the pool diameter increased or the convective heat flux per unit pool surface increased.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.