CONVECTION VELOCITY-MEASUREMENTS IN THE CREVICES OF FURNITURE

Previous to this study, research has shown that small air velocities can strongly influence the ignition propensity of a cigarette on upholstered furniture simulations. However, data were not available to determine if such velocities existed in practice- The two objectives of the current effort were to determine (1) the typical steady velocities near the cushion of a warm chair due strictly to free convection and (2) the typical unsteady velocities near the crevice of a warm chair due to a combination of free convection and forced convection as a result of a person vacating the chair. Typical steady velocities were 40 mm/s. Typical velocities in the unsteady conditions were 15 mm/s. For the unsteady conditions large velocities remained long after the chair cooled to room temperature due to large vortices in the flow with long time constants.