Performance Evaluation of a Small-Scale Turbojet Engine Running on Palm Oil Biodiesel Blends

The experimental and simulated performance of an Armfield CM4 turbojet engine was investigated for palm oil methyl ester biodiesel (PME) and its blends with conventional Jet A-1 fuel. The volumetric blends of PME with Jet A-1 are 20, 50, 70, and 100% (B20, B50, B70, and B100). Fuel heating values (FHV) of each fuel mixture were obtained by calorimetric analysis. The experimental tests included performance tests for Jet A-1 and B20, while the performances of B50 to B100 were simulated using GasTurb 11 analytical software. In terms of maximum measured thrust, Jet A-1 yielded the highest value of 216？N, decreasing by 0.77%, 4%, 8%, and 12% with B20, B50, B70, and B100. It was found that B20 produced comparable results compared to the benchmark Jet A-1 tests, particularly with thrust and thermal efficiency. Slight performance penalties occurred due to the lower energy content of the biodiesel blends. The efficiency of the combustor improved with the addition of biodiesel while the other component efficiencies remained collectively consistent. This research shows that, at least for larger gas turbines, PME is suitable for use as an additive to Jet A-1 within 50% blends. 1. Introduction There is a general consensus within the literature that fossil fuel feedstock used for the production of aviation-grade kerosene fuel is dwindling. Koh and Ghazoul [1] expected a peak oil production scenario within the years 2010–2020, assuming that global oil consumption increases to 118 million barrels per day in 2030. Nygren et al. [2] projected that civil aviation traffic growth will increase at a rate of 5% per year, while fuel consumption will increase at 3% per year. Lee et al. [3] projected that aviation traffic growth will increase by 4.5% to 6% per year over the next twenty years, with traffic doubling every 15 years. This is further supported by the recent report by Deloitte [4], whereby passenger travel demand is expected to increase 5% over the next 20 years, contributing to increases in aircraft production. Despite the improvements in aircraft fuel efficiency since 1960 [5], further efforts need to be made in order to mitigate the dependency on traditional fuel sources and to replace current petrol-based fuels. Biodiesel is produced through the transesterification of pure vegetable or organic oils by replacing the triglyceride molecules with lighter alcohol molecules such as methanol or ethanol. The reaction is carried out with a strong base catalyst, producing glycerol in addition to transesterified vegetable oils (biodiesel) [6]. Canakci et al. [7] claimed that