Engine Power Loss Research Articles

Heat and Mass Transfer for Ice Particle Ingestion Inside Aero-Engine

Ice crystal icing has been found to be the prime culprit for aero-engine internal icing. Internal icing and the following ice shedding may cause the engine power loss, flame-out, and even damage to the compressor components. In this paper, the ice particle ingestion process and the interaction between the particles and components are discussed. Heat and mass transfer models are built for two ideal conditions. Results from a case study reveal that the melting rate for the ice particle covering with water film is much higher than that for bare particles. Those ice particles with a size beyond a critical diameter cannot be melted completely before entering into the combustor. The study can provide further consideration of the mechanism of engine “flame-out” and component impact damage.

Fuelling of aircraft radial piston engines by ES95 and 100LL gasoline

The cost of maintaining aeroplanes is still considerable. It concerns especially operation cost where fuel is a substantial part. At the moment the special 100LL gasoline is used to fuel aircraft piston engines. It is about 20% more expensive than ES95 gasoline featuring comparable properties. The article shows the results of test-bed research conducted on the radial piston aircraft engine fuelled by aircraft 100LL gasoline and automotive ES95 gasoline. The object of research was ASz-62IR engine by WSK PZL-Kalisz that was equipped with an experimental fuel injection system. Power, fuel consumption, head temperatures and indicated pressure in cylinders were analysed in the selected typical operating points. The testing was carried out in steady state. It was proved that it is possible to exchange fuels with no engine power loss and merely an insignificant increase of fuel consumption but with significant increase of IMEP cycle-to-cycle variation.

Prediction of Helicopter H-V Zone and Cueing the Emergency Maneuver After Power Loss

Prediction of Helicopter H-V Zone and Cueing the Emergency Maneuver After Power Loss The paper presents the results of simulation method for prediction of helicopter H-V zone envelope in the case of engine power loss. Depending on the loss rate of available power, the emergency maneuver for flight continuation is calculated, or the autorotation landing is predicted. The realization of an airborne device with in-built calculating procedure and graphic presentation of H-V zone predicted limits can improve safety level of helicopter flight, and can cue the pilot to make proper decision in emergency conditions. The results of emergency maneuver simulation were verified by comparing them with flight tests of Mi-2Plus helicopter for partial power unit failure, and with records of SW-4 helicopter autorotation landing. The operation of measurement-recording module, which consists of GPS receiver, inertial measurement unit and a computer of PC-104 standard, was checked during flight tests of a radio-controlled helicopter model.

The comparison of the operating parameters in an aircraft radial piston engine fuelled by 100LL and ES95 gasoline

Small aviation develops very dynamically. This is a result of airplane general availability and their lower prices. At the same time, however, the maintenance costs of airplanes increases. It particularly concerns the operation cost where fuel is its substantial part. At the moment special 100LL gasoline is used to fuel aircraft piston engines. It is about 20% more expensive than ES95 gasoline of comparable properties. The paper shows the results of test-bed research conducted on the radial piston aircraft engine fuelled by aircraft 100LL gasoline and automotive ES95 gasoline. The object of research was ASz-62IR engine by WSK Kalisz fitted with an experimental fuel injection system. The power, fuel consumption and cylinder head temperatures were analysed in the selected typical operating points. The testing was carried out in a steady state. It was proven that it is possible to exchange (replace) fuels with no engine power loss with a miniscule increase of fuel consumption.

Fatigue failure of a compressor blade

A helicopter in a commercial flight was substantially damaged during a hard landing following a loss of engine power at Northwest region of Brazil. The pilot and passengers reported no injuries. Initial investigations pointed out absence of any damages by foreign objects. The accident was due to the failure of a blade from compressor section. Failure analysis of 4th stage disk showed that the blade failed due to fatigue which started from corrosion pits.

Driving Load Estimation with the Use of an Estimated Turbine Torque

In this paper, a vehicle driving load estimation scheme in the form of a linear state observer is presented. The signals used in the observer are the transmission output speed and driven wheel speed, which are readily available in any vehicle equipped with an automatic transmission. Because the observer requires the turbine torque as input, the turbine torque itself has been estimated using a neural network. The proposed observer has been evaluated using a vehicle simulator in various driving situations considering transmission oil temperature variations, engine power losses, and variation of load conditions. A nonlinear vehicle powertrain model has been used in the development of the vehicle simulator. The effectiveness of the proposed scheme has been tested through experiments.

Experimental evaluation of Diesel engine performance and emission using blends of jojoba oil and Diesel fuel

An experimental evaluation of using jojoba oil as an alternate Diesel engine fuel has been conducted in the present work. Measurements of jojoba oil chemical and physical properties have indicated a good potential of using jojoba oil as an alternative Diesel engine fuel. Blending of jojoba oil with gas oil has been shown to be an effective method to reduce engine problems associated with the high viscosity of jojoba oil. Experimental measurements of different performance parameters of a single cylinder, naturally aspirated, direct injection, Diesel engine have been performed using gas oil and blends of gas oil with jojoba oil. Measurements of engine performance parameters at different load conditions over the engine speed range have generally indicated a negligible loss of engine power, a slight increase in brake specific fuel consumption and a reduction in engine NOx and soot emission using blends of jojoba oil with gas oil as compared to gas oil. The reduction in engine soot emission has been observed to increase with the increase of jojoba oil percentage in the fuel blend.

Stratigraphy and textural characteristics of the 1982–83 tephra of Galunggung volcano (Indonesia): implications for volcanic hazards

The Galunggung volcano in western Java (Indonesia) was the site of historical activity in 1822, 1894, 1918, and 1982–83, located in a pre-historical horseshoe-shaped caldera. In 1982–83, a nine-month-long eruption generated successively (1) ash-and-scoria flows channeled in two valleys and extending 6km from the vent (vulcanian phase 1), (2) surges and ash falls related to the excavation of a wide maar crater, with ash columns 20km high (phreatomagmatic phase 2), and (3) ash and scoria falls that built a small cone inside the maar crater (strombolian phase 3).During phreatomagmatic phase 2, there was a significant increase of explosivity. Paradoxically, the magma composition had evolved from andesite to primitive magnesian basalt. Jet-plane incidents were recorded during this period: on the June 24 and July 13, 1982, two Boeing 747 aircraft experienced engine power loss when passing through the plume.The vertical variations of grain sizes and xenolith contents of pyroclasts were measured in the 1982–83 eruptive deposits. We show that a progressive increase of the ratio of xenolith versus juvenile magma before the end of vulcanian phase 1 heralded the increase of explosivity leading towards phreatomagmatic phase 2. In the same way, the decrease of the same ratio at the end of the phreatomagmatic phase 2 heralded the decrease of explosivity and the onset of strombolian phase 3. The transition from phase 1 to phase 2 is also marked by a slight but continuous decrease of the vesicularity index of juvenile clasts.We emphasize the increasing efficiency of groundwater/magma interaction during the eruption. The increasing interaction and renewed explosive activity occurred after a period of rest, during which additional groundwater was supplied in the vicinity of the magma column.The data suggest that it would have been possible to predict as soon as April–May 1982 the transition from vulcanian to phreatomagmatic activity, and consequently the corresponding increase in explosivity.

Acoustocyclone filter concept for soot retention in automotive diesel engines

Fine-particle soot emissions are an intrinsic problem of diesel-powered vehicles. A number of car manufacturers have already begun marketing diesel vehicles with particle emission control equipment in an effort to address the problem. While technical solutions exist to reduce the number of fine diesel exhaust particles, these systems tend to be bulky and poorly resistant to high mechanical stresses and high temperature operation. Filters tend to get blocked, causing unwanted pressure increases in the exhaust line and an eventual loss of engine power and fuel efficiency. The concept study presented here focuses on a compact particle retention device that will generate only a small pressure drop, while efficiently filtering fine and coarse particle exhaust emissions. Based on a technology developed for coal-fired power plants, the new filtration unit will make use of a two-stage collection system consisting of a conventional cyclone and an acoustic aerosol agglomerator. The approach will build on the concept of aerosol preconditioning to improve the retention efficiency of a conventional cyclone. This improvement will be achieved through initial agglomeration of the fine particles with larger soot particulates, and subsequent filtration of the preconditioned aerosol in a cyclone collector.

An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

Prediction of the effect of injection parameters on NOx emission and burning quality in the direct injection diesel engine using a modified multizone model

Combustion process in a quiescent chamber diesel engine is modelled using a multizone model. This model divides the cylinder charge into two zones, namely the unburnt zone (surrounding air) and the burnt zone (fuel spray with entrained air). The burnt zone is subdivided into 16 concentric sprays, instead of only eight sprays as in previous work, each one with its own temperature and composition. Liquid fuel, fuel vapour, air and products of combustion are assumed to be present in each zone. Real gas relations are used to calculate the properties of the mixture while products of combustion are assumed to be in chemical equilibrium at local temperature. The extended Zeldovich mechanism is used to predict the NO x formation. The cylinder pressure, temperature, heat release rate, NO x rate and concentration are calculated. For different injection pressures, injection advance angles and different fuel orifice hole diameters, the results show that the model can predict the measured cylinder pressure with high accuracy but it predicts the measured heat release rate and NO x emission rate with moderate accuracy. In addition, the effect of injection parameters on the NO x emission and engine power is predicted and it has been shown that NO x emission can be reduced without noticeable loss of engine power. This can be done by appropriate choice of injection pressure, injection advance angle and fuel nozzle hole diameters.

Flex Cycle Combustor Development and Demonstration

An innovative, “flex-cycle” combustion system has been developed for the Garrett Model 400-1 Integrated Power Unit (IPU), a 425 shp (317 kW) gas turbine engine designed for use on future fighter aircraft. Demonstration of this system required real-time transient operation of the combustor in a full-scale test rig. The transient testing was unique, having been performed with an electronic control, which modulated all combustor operating parameters according to programmed engine component maps, drag curves, fuel schedules, and selected ambient test conditions. The axially injected annular combustor is capable of engine starts in two seconds, as well as producing 200 shp (149 kW) for emergency use at all altitudes up to 50,000 ft (15,240 m). The combustion system is capable of switching operation from the emergency power stored energy (SE) mode to the normal-air breathing (NAB) auxiliary power mode without loss of engine power. The flex-cycle combustor supplies emergency power in the SE mode with a temperature rise of 2200°F (1222°C) and in the NAB mode with a temperature rise of 1600°F (889°C). Specific features that make these requirements possible include air-assisted simplex airblast fuel atomizers with integral check valves, and effusion-cooled combustor liner walls. This paper describes the flex-cycle combustion system design, test methods used, and significant test results. Steady-state performance, in both the SE and NAB operating modes, and real-time transient test results are discussed. The transient testing included rapid starts as well as transitions from the SE to NAB operating regimes.

Erosion Study of Radial Flow Compressor With Splitters

Gas turbine engines operating in areas where the atmosphere is polluted by small solid particles are examples of machines operating under particulate two-phase flow conditions. The presence of solid particles in the working media leads to erosion and loss of engine power. In the present paper, particle trajectories are calculated by direct integration of the particle equations of motion through a compressor impeller with two different size splitters. Particle collisions with the blade, hub, and casing surfaces are determined. Erosion caused by the particle collisions with the compressor surfaces is calculated.

PLASMA BEHAVIOR IN AN OSCILLATING-ELECTRON ION ENGINE

The behavior of the plasma within an oscillating-e lectron ion engine was investigated in detail. It was found that certain conditions of gas pressure, magnetic field strength, and cathode emission current are required to maintain the accelerating electrostatic field in the plasma within the engine. In addition, the investigation revealed two types of transient phenomena in the discharge which can occur under certain conditions. The first is a pulsing or fluctuating mode of operation which appears to be caused by depletion of gas within the engine due to the pumping action of the discharge. The second is an azimuthal rotation of plasma perturbations in the range of frequencies of 10 to 50 kc as a result of E?- X Bz/Z?2 drifts. There is a possibility that this rotation may result in an enhanced diffusion of electrons across the containing magnetic field and hence contribute to engine power losses.