Greg Pucher

Emissions From a Gas Turbine Sector Rig Operated With Synthetic Aviation and Biodiesel Fuel

Differences in exhaust emissions, smoke production, exhaust pattern factor, deposit buildup, and fuel nozzle spray characteristics for various blends of conventional commercial jet fuel (Jet A-1) with synthetic and biodiesel formulations were investigated. Three synthetic fuel formulations and four fatty acid methyl esters (FAMEs) were evaluated as such. The synthetic fuels were tested in both neat (100%) and 50% by volume blends with Jet A-1, while the FAME fuels were blended in 2% and 20% proportions. The combustion chamber sector rig, which houses a Rolls Royce T-56-A-15 combustion section, was utilized for emissions, deposits, and exhaust pattern factor evaluation. A combustion chamber exhaust plane traversing thermocouple rake was employed to generate two-dimensional temperature maps during operation. Following combustion testing, several combustion system components, including the combustion chamber, fuel nozzle, and igniter plug, were analyzed for relative levels of deposit buildup. A phase Doppler anemometry system was employed to determine differences in droplet size distributions, while an optical spray pattern analyzer was used to compare the spray pattern for the various fuel blends as they emerged from the T-56 nozzle.

Improving the Fuel Efficiency of Light-Duty Ethanol Vehicles - An Engine Dynamometer Study of Dedicated Engine Strategies

A machine for drilling and routing of printed circuit boards comprises a support mechanism for supporting a stack of superimposed boards in a support plane and for moving the stack of boards in a first predetermined direction parallel to the support plane. A tool spindle is disposed above the stack of boards and is movable in a second direction parallel to the support plane and perpendicular to the first direction, so that the positions of the holes to be drilled in the PC-boards can be determined in a coordinate system having the first and second directions as its X-axis and Y-axis respectively. For holding the stack of PC-boards pressed together during the drilling or routing operation, the machine comprises press rollers, which exert a pressure force upon the stack of PC-boards towards the support mechanism. The press rollers are arranged on both sides of the tool spindle with their axes of rotation parallel to the direction in which the tool spindle can be moved, i.e. the Y-direction.

Can-Annular Combustion Chamber Surface Temperature Measurements and Damage Signatures at Operationally Representative Conditions

An experimental program which investigated the surface temperature distribution of a contemporary gas turbine combustion liner is presented. An array of 65 embedded surface mounted thermocouples was installed on a Rolls Royce/Allison T56 combustion liner and exposed to combustion conditions in the Combustion Chamber Sector Rig (CCSR) at the Royal Military College of Canada. The CCSR was operated at two test points to simulate idle and cruise modes of operation. Corresponding exhaust temperature measurements were taken in the test combustion chamber exhaust plane with a sweeping thermocouple rake. These efforts were the latest in a multi-year program to investigate the impact of service wear related geometric deformations of combustion liners and damaged/fouled fuel nozzles on the exit temperature profile from typical combustion chambers. It has been previously ascertained that real-world geometric anomalies in the T56 combustion chambers, particularly in the transitional zone, can modify the exhaust temperature profile to a sufficient degree so as to risk hot section damage due to excessive heat exposure. The collection and analysis of surface temperature data represents a useful extension of the knowledge base of the T56 combustion system within the context of the overall program and is paramount to upcoming numerical modelling efforts aimed at assessing hot section damage risks.Copyright

Development of a Spark Discharge PM Sensor for Measurement of Engine-Out Soot Emissions

Filter paper methods are well recognized as an effective means of measuring soot emissions from diesel engines. However, these methods provide an average soot value over a relatively long time period, rather than a real-time signal. Real-time measurements of engine-out soot emissions that could track changes in soot levels during transient operating conditions would be useful for the optimization of engine control strategies such as exhaust gas recirculation. This paper presents experimental results obtained using a real-time PM sensor based upon a spark discharge measuring principle. Like traditional filter paper devices, it is sensitive to the carbon or soot component of the particulate matter emitted by diesel engines. The sensor was tested on a turbocharged diesel engine, and compared with reference measurements of Filter Smoke Number (FSN) from an AVL 415s smokemeter. Improvements to the sensor made it possible to measure soot levels at FSN values over 3.5, while retaining good sensitivity below FSN values of 0.1. The sensor signal showed a high correlation with the reference FSN measurements. This correlation was used to develop a signal processing technique so the sensor provided a real-time signal for predicted FSN. Conversion of the FSN values to mass concentration values (using published techniques for the reference instrument) indicated that the output of the spark discharge soot sensor was nearly linear with mass concentration over a substantial portion of the measuring range. The sensor showed a response time of under 2 seconds to step changes in FSN levels.© 2010 ASME

Emissions Testing From the Use of Various Biodiesel Blends in Representative Canadian Army Equipment

A comprehensive series of emissions measurements were taken from two pieces of equipment used by the Canadian Forces. A field kitchen burner unit and the engine from the Light Armoured Vehicle III (LAVIII) were operated using two base fuels: low and ultra low sulphur diesel fuel blended with three different biofuels. Methylesters from canola, tallow and yellow grease were mixed in a range of volumetric proportions from 0 to 20%. Additionally, both very low sulphur diesel and aviation turbine fuel (JP-8) were tested against neat low sulphur diesel fuel. The complete chemical analysis conducted on all test fuels will not be presented here. A full range of gaseous emission measurements were obtained including oxides of nitrogen, unburnt hydrocarbons, carbon monoxide and dioxide and limited sulphur dioxide measurements. Two means of monitoring particulate matter were used with one proving to be more effective than the other. Novel techniques were used to obtain the burner unit emissions results and the AVL 8-mode test sequence was applied to the Caterpillar engine from the LAVIII. Although emission trends were detected, levels were often on the margins of perceptibility of the gas analysis system, and atmospheric conditions were challenging. Nevertheless, a methodology was developed and refined. Some correlations were made between the chemical analysis and emissions results. The testing will allow the Canadian Army to estimate its emissions footprint.Copyright

Flame-Out Detection for Gas Turbine Engines Based Upon Thermocouple Signal Analysis

This paper describes an experimental study to examine the potential of using Exhaust Gas Temperature (EGT) thermocouples for prompt flame-out detection in gas turbine engines. The approach taken involved accelerating the response of a shielded, slow response thermocouple using electronic processing of the signal. Thus, the abrupt drop in temperature characteristic of a flame-out could be detected within a much shorter time period than would be possible through a conventional thermocouple temperature measurement method. This was intended to provide a robust alternative to existing optical flame-out sensors which have fast response but can be susceptible to false flame-out indications due to window sooting. A production EGT thermocouple with online electronic processing was compared with a production optical flame sensor from a GE F-404 and a laboratory photodiode sensing system. The devices were tested in a full scale GE J-85 combustion chamber sector rig with optical access. The results showed that the thermocouple flame sensor had a response time to flame-outs of less than 100 ms. This was much faster than a conventional thermocouple, but still an order of magnitude longer than the optical flame sensor. However, whereas the optical flame sensor could yield ambiguous results about the presence of flame under some conditions, the thermocouple flame sensor provided a clear indication of flame-out events for all the conditions that were tested.Copyright