Biodiesel Production from Waste Frying Oils by Potassium Methoxide Supported on Activated Carbon Catalysts from Lignocellulosic Biomass

Various carbon-rich solid catalysts are evaluated for the synthesis of biodiesel from waste frying oil. The study results showed that the use of activated carbon made of corn stalk could increase the biodiesel yield by 7%. The heterogeneous carbon-based catalysts made of lignocellulosic residues could successfully improve the quality of biodiesel properties. The results obtained revealed that the biodiesel properties, including relative density (852–900 kg·m−3) and kinematic viscosity (2.4–3.9 mm2·s−1), are in compliance with the standard limits of ASTM and the European Biodiesel Standard, suggesting that the biodiesel produced would be decent as a diesel fuel that potentially can minimize the serious damage of engine parts, and prolong the engine life.

Comparative Study of a Powerplant Life Consumption Rate When Installed in Two Different Aircraft Variants

The Hellenic Air Force (HAF) operates both EMB-145 and EMB-135 LR versions of Embraer aircraft, used in surveillance and civil missions respectively. These aircraft are equipped with the same version of Rolls Royce, AE 3007 turbofan engine. This study aims to quantify and compare the life consumption rate of this engine when installed in each of the two aircraft variants. Two typical missions, one for each variant, were constructed based on mission profile data dictated by the aircraft commanders. For each mission profile segment, corresponding engine data were matched out of the engine recordings archives held by the Hellenic Air Force. The life consumption rate was based on the Low Cycle Fatigue (LCF) and creep cumulative detrimental effect on the rotor blades of the 1st High-Pressure Turbine stage. For the LCF, the rainflow method was used to determine the respective loading cycles, whereas the Larson - Miller parameter method was used to determine the consumed life fractions due to creep. The main conclusion of the study was that the engine when installed in the EMB-145 military variant, is much more loaded. Despite the fact absolute life consumption values could hide a great level of uncertainty, the comparative outcomes wherein errors are, to a certain extent, cancelled out, could be used as a rule of thumb when monitoring engine life consumption rates.

Research of operational features of heat accumulators using on motor transport

Preheating of the engine is often used to facilitate the start of the internal combustion engine in winter, which provides an opportunity not only to increase the comfort of starting, but also to reduce exhaust emissions, increase engine life. That is why the choice of optimal heat storage materials, which on the one hand would have sufficient heat efficiency and on the other hand would satisfy the operational requirements regarding corrosion activity, etc., is an urgent problem. In particular, the barium octohydrate used in our studies is corrosive, although it has a high heat of phase transition heat. The media investigated the media that are ordinary working fluids for heat transfer during heat accumulation: antifreeze, antifreeze, water; heat-accumulating materials – paraffins and octohydrates, and as investigated in relation to corrosion of material steel St3 was considered. The working temperature range was used in the work. It was found that the corrosion rate of 3 mm per year in antifreeze and antifreeze environments requires the choice of anti-corrosion coating or the search for new material that will react.

An analytical model of the replacement costs of aircraft engine life-limited parts

Purpose The purpose of this paper is to present novel recursive expressions for modelling the replacement costs of aircraft engine life-limited parts during shop visits to assist engine operators in both evaluating their decisions regarding the applied life-limited parts management strategies and tracking the replacement costs consistently throughout the life of the engine. Design/methodology/approach The replacement costs of aircraft engine life-limited parts are modelled analytically in this research, which strives to quantify the costs of used and unused lives of the replaced parts, incurred during engine shop visit events. Inputs for this model include the list price of life-limited parts, the replacement decisions made on all previous shop visits and the number of cycles the engine has operated at different thrust ratings on all previous operating intervals. Findings The average annual escalation rate of life-limited parts list prices was shown to range from 5% to 7%. The presented model is not only suitable for calculating the costs of used and unused lives of life-limited parts during past engine shop visit events but also for application in the life-limited parts replacement cost forecasting and optimisation models. Originality/value Uniquely derived recursive expressions represent the final result of the developed model which, to the authors’ knowledge, had not been studied elsewhere in the academic literature. The analysis of aircraft engine life-limited part list prices carried out to account for the average annual escalation rate enables the prediction of replacement costs during subsequent shop visits.

Adjustment and Validation of Monitoring System Algorithms on the Simulated Historical Data of an Aircraft Engine Fleet

In the field of gas turbine diagnostics, a significant gap is observed between the variety of proposed and investigated diagnostic solutions and a narrow group of algorithms employed in real monitoring systems. One of the explanations is that diagnostic algorithms of a monitoring system (system components) are usually developed and verified separately from each other. An additional explanation is related to simplified simulated data used to verify the algorithms. The present paper aims to adjust and validate the joint operation of the algorithms of a gas turbine monitoring system during the whole lifetime. The software tool called the Propulsion Diagnostic Method Evaluation Strategy (ProDiMES) provides the input data. This tool realistically simulates the steady-state parameters of an aircraft engine fleet. The simulation embraces a total engine life and includes different variations of deterioration and various engine, actuator, and sensor faults. Using ProDiMES, some diagnostic solutions have been verified so far. However, they do not include all necessary monitoring system components, use a short fixed-time interval of input data, and do not analyze long-term deterioration. In contrast, this paper presents an attempt to enhance a whole diagnostic process. It considers the operation of various data-driven algorithms of a monitoring system during engine life. The paper focuses on the tuning of the algorithms themselves and adjustment of their interactions.

Turboprop Engine Loading During High and Low Maneuver Intensity Flight Mode

The life consumption rate of the aircraft engine is a vital input for aircraft operators who aim to an efficient fleet management. T6 aircraft, propelled by the PT6 turboprop engine, is operated by the Hellenic Air Force, both for training and aerobatic purposes. The current study focuses on quantifying and comparatively assessing the engine life consumption rate for the following missions: i) An “aerobatic” mission which is a typical high intensity maneuver flight and ii) a “training for patrol” mission, representing a typical low intensity maneuver flight. Missions were selected with the criterion of setting the lowest and the highest possible engine loading during a certain mission. In other words, the goal of the study is to define the extent of the loading the engine can encounter as a propulsion system of the T-6 aircraft during a certain mission. This is the first step before proceeding in setting up a methodology for continuously monitoring the engine life consumption rate in support of the squadron flight management plan. The study was based on real time data recorded during the respective flights. An engine model built using “GasTurb” gas turbine simulation software was used to fill in engine operating data at stations where recordings have not been taken. Engine life consumption was based on creep and low cycle fatigue failure mechanisms of the first gas generator turbine stage. Creep life fractions were calculated based on the Larson-Miller parameter curves and the fatigue cycles were counted using the rainflow method. The study showed that the life consumption is about 10 times lower when the aircraft is operated at a low loading mode as opposed to a high loading mode.

Evaluation of heavy-duty vehicles engine life with controlled modification of engine oil

The article presents the method of controlled modification of engine oil, as well as the results of operational studies to assess the service life of heavy-duty vehicle engines. The method of controlled modification of engine oil includes a system of five levels of information helping to assess the technical condition of engines of heavy-duty vehicles, including mining dump trucks. The first level of the methodology includes the use of subjective methods for determining the technical condition of engines by its external manifestations. The second level of the methodology includes the use of simple instrumental methods and means of obtaining diagnostic information about the technical condition of the engine and its subsystems. The third level of the technique involves the use of a drip test of engine oil. The fourth level of the methodology includes the chemical analysis of engine oil samples. The fifth level of the technique involves spectral analysis of engine oil to determine the presence of metals.