Measurement of Air Flow Outside a Burning Cigarette during a Puff using Particle Image Velocimetry

Abstract

In order to clarify the mechanism for the generation of cigarette smoke, the combustion mechanism of a burning cigarette during a puff was investigated by focusing on air transfer. In particular, the air flow distribution outside a burning cigarette was observed and related to the aerodynamic effects of the cigarette paper and the puffing rate. The air flow rate was measured by Particle Image Velocimetry (PIV), using olive oil droplets as the tracer particles. It was found that air does not flow into the tip of the burning cigarette and that the air flow was concentrated at the region -2 to 2 mm around the cigarette paper char-line. This behavior was independent of the cigarette paper basis weight. When the puffing rate was changed from 2.5 to 35 mL/s, the air flow was concentrated at a region close to the cigarette paper char-line and the maximum velocity around the cigarette paper char-line increased with the puffing rate.

A Profile of the Heat Generation Inside a Cigarette During Puffing

“…The heat generation rate behind the paper char-line for cigarette B slightly increased compared to cigarette A. Since the air is always flowing into the region close to the paper char-line during puffing regardless of cigarette paper basis weight applied in this study (4), the position of the air inflow into the burning cigarette should be determined by the burn rate of the cigarette paper during puffing. Accordingly, if the burn rate of the cigarette paper increases, it is assumed that the amount of air supply into the high temperature tobacco bed behind the paper char-line should decrease.…”

“…He derived the important finding that the region of the maximum temperature and strong oxygen consumption is located behind the paper char line towards unburnt tobacco column. Many reports have presented data on the air flow field outside a burning cigarette during puffing (1,3,4). These studies indicate that the air mainly enters from a region close to the paper char line.…”

Evaluation of Combustion of a Shredded Tobacco Bed Using a Reactor to Produce Reverse Smolder: Influence of Properties Related to Mass Transfer on Combustion of the Bed

“…In a further study, BAKER also showed that above 400 C the mass transfer of oxygen to the tobacco surface controls the tobacco combustion rate (4). To investigate details of the air inflow position into the burning cigarette and the flow rate outside the cigarette, we measured the transient change of the flow rate distribution outside the burning cigarette during puffing directly using the Particle Image Velocimetry system (5). We also estimated the net heat generation rate at various positions inside the burning cigarette during puffing by calculation from the heat balance equations using the experimental temperature profiles (6).…”