IGNITION DELAY TIME INVESTIGATION OF GTL FUEL BLENDS

Abstract

Ignition delay is a vital combustion characteristic of any fuel that directly affects the development of internal combustion engines (ICEs) and exhaust emissions, especially in diesel engines. Considering the global interest in alternative fuels, GTL (Gas to Liquid) can be considered one of the promising new alternative fuels, especially for compression Ignition engines (CIE). In this dissertation, an investigation of this property experimentally for different types of heavy hydrocarbon fuels such as diesel, GTL, GTL/diesel blends, and GTL/biodiesel blends under a wide range of operation conditions like initial pressure, initial temperature and equivalence ratio; starting from a deep survey of the previous studies. The shock tube facility is used to investigate the fuel's combustion delay above. The works initially characterized the shock tube at Qatar University experimentally and numerically by determining the best location for the diaphragm (three different diaphragm positions (1m, 2m, and 3m)) alongside pressure ratio across the diaphragm (five pressure ratios (6-10)) since those parameters affect the tube performance and then the measurement of the ignition delay. The parametric study results showed that at high-pressure ratios, diaphragm positions 1 and 3 could generate a 7.4% rise in the Mach number of the incident shock wave compared to the diaphragm position-2 model. Moreover, the diaphragm position-3 model tends to have a 2% increase in the temperature behind the reflected shock wave compared to the other two positions.The ignition delay results are presented for three types of fuel: Diesel, GTL, and 50-50 Diesel-GTL blend for a variety range of pressure (6, 10, 14, and 20 bar), temperature (980 to 1120 K), and equivalence ratios (0.5, 0.7, 1.0, and 1.3). The ignition delay time measurements confirm a previous study by Joshua et al. that GTL has the shorter ignition delay period for all conditions. The Diesel-GTL blends data vary in different temperatures; however, it was noted between Diesel and GTL.