Laminar Flow Reactor
The laminar flow reactor (LFR) is used for the detailed chemical kinetic investigation of the low temperature auto-ignition chemistry of premixed air/fuel mixtures of diesel-like gaseous and liquid fuels at atmospheric pressure. It is applied to measure first stage ignition delay times and stable intermediate species of the low temperature combustion process with gas chromatography-mass spectrometry (GCMS).
In order to obtain a uniform and controlled temperature, the LFR is placed within an approximately isothermal oven. It consists of a quartz glass tube, which has a helical shape of four coils, with an inner diameter of 20.6 mm and a wall thickness of 2.2 mm. The overall length of the LFR is 4800 mm. Fuel is injected into the air flow using a specially designed injector, which is placed within the main pipe just before the inlet. The oncoming oxidizer and fuel flow are heated to the same temperature as the oven and the glass tube located therein. The vaporized or gaseous fuel is rapidly mixed with the air at the beginning of the reactor (tign > 20*tmix). With a spacing of 89 mm, the LFR is equipped with 48 N-type thermocouples in order to record temperature profiles and determine the ignition location. Together with the inlet flow rates, they are used to obtain the first stage ignition delay times. The heat loss of the gas mixture after the first stage of ignition leads to a freezing of the chemical reactions, which enables the evaluation of intermediate species in the exhaust gas.
Figure: Schematic setup of the laminar flow reactor with the GCMS