Time and spatially resolved in-situ determination of temperature, pressure and gas phase concentration of selected smoke constituents inside a burning superslim cigarette. Part I – Thermophysical mapping
Superslim cigarettes in China are a relevant product category on the market. Accurate determination of key thermo-physical and -chemical parameters in superslim cigarettes are essential for the mechanistic understanding of combustion as well as pyrolysis processes. The objective of this study is to combine in situ temperature and pressure measurement techniques with a fast sampling technique to obtain detailed physical and chemical information within a burning superslim cigarette. The first part of this comprehensive mechanistic study on superslim cigarettes presents the results of the temperature and pressure profiles inside the burning cigarette. A reference superslim format test piece (circumference: 17 mm) was mounted on a micrometre test bench to ensure precise insertion of an array of 0.254 mm thermocouples for gas-phase temperature and another multiple 0.35 mm diameter quartz tubes for pressure measurements. For chemical characterization, a single heated 0.5 mm sampling microprobe, coupled to a single-photon soft ionisation (SPI) mass spectrometer, was also inserted at different sampling points. Synchronisation among the different measurement techniques was achieved by mapping two probes at the same time (i.e. temperature and pressure or temperature and chemistry). Dedicated software was developed to integrate the data sets from multiple sampling points for visualization of the synchronized physical and chemical data. The highly heterogeneous combustion system in a superslim cigarette was mapped for the first time to obtain a fundamental thermophysical understanding. The data from temperature and pressure measurements were used to calculate the axial gas velocity, which is a key parameter in understanding the complex toxicant formation processes.