scholarly journals POSSIBLE HYBRID PROPULSION CONFIGURATION FOR TRANSPORT JET AIRCRAFT

Aviation ◽  
2016 ◽  
Vol 20 (3) ◽  
pp. 145-154 ◽  
Author(s):  
Sergio CHIESA ◽  
Marco FIORITI ◽  
Roberta FUSARO
Keyword(s):  
Electric Motor ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Preliminary Design ◽  
Combustion Engines ◽  
Jet Engines ◽  
Electric Motors ◽  
Hybrid Propulsion ◽  
Air Turbine ◽  
Innovative Solution

This research is aimed at studying the possible advantages of installing, for a hybrid propulsion aircraft, electric motors and related propellers into the dedicated supplementary nacelles. This innovative solution is different from the configuration, already studied for a regional turboprop (Chiesa et al.2013), in which the electric motors are in the same nacelles of the internal combustion engines. As it has been expected, it offers the advantages of avoiding mechanical links between the two units and, more importantly, can also be applied to jet aircraft. In fact, the main contribution of electric motors is expected during ground operations, take-off and descent phases (i.e. at low speed), in which it can be useful to integrate the propellers or even substitute the jet engines with them. At high speed, the propellers, of course, are configured in order to reduce drag. When considering the design of a new airliner concept, a preliminary design study is necessary to optimize the location of the supplementary nacelles. The nacelles, which only hold the electrical motor, can also be considered retractable, as is usual for a RAT (Ram Air Turbine). Please note that in the hybrid propulsion context, the RAT function can be clearly allocated to the electric motor, with the advantages of optimizing drag at high speed, taking into account installation problems.

The Practical Design of Turbocharger Turbines Using a Throughflow-Based Optimisation Process

2012 ◽  
Author(s):  
Graham D. Cox
Keyword(s):  
Knowledge Base ◽  
Electric Motor ◽  
Internal Combustion Engines ◽  
Preliminary Design ◽  
Combustion Engines ◽  
Two Stage ◽  
General Applicability ◽  
Choice Of Major ◽  
Practical Design ◽  
Selection Of

The modern trends in automotive turbocharger applications are towards the boosting of smaller internal combustion engines and more advanced systems including two-stage, turbo-compounding and hybrid electric-motor assist. Off-the-shelf turbochargers will become a smaller share of the market and the choice of major parameters for the compressor and turbine, e.g. speed and diameter, will fall outside of the manufacturer’s knowledge base. The selection of the compressor and turbine may even be independent. The only certainty is that the turbomachinery will have to be small, cheap and efficient. To provide some guidance to the turbine designer, this paper presents the results of a study in which practical designs have been generated to cover the range of conceivable parameters, presented in non-dimensional terms to provide general applicability. All the designs are generated using a throughflow-based optimisation system in which the candidate geometries are assessed against mechanical as well as aerodynamic and inertia targets. Analysis of the results gives clues to the form of the basic empiricism that would be of use in the preliminary design of automotive turbocharger turbines.

scholarly journals The Changes of Ergonomic Engine Vibroacoustic Response Regarding Their Development

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4215
Author(s):  
Radosław Wróbel ◽  
Lech Sitnik ◽  
Monika Andrych-Zalewska ◽  
Łukasz Łoza ◽  
Radostin Dimitrov ◽  
...  
Keyword(s):  
Human Health ◽  
Power Density ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Spectral Power ◽  
Spectral Power Density ◽  
Steering Wheel ◽  
Combustion Engines ◽  
Head Restraint ◽  
Vibroacoustic Response

The article presents the results of research on the vibroacoustic response of internal combustion engines mounted in a vehicle. The vehicles studied belong to popular models, which became available in successive versions. Each group included vehicles of the same model of an older generation (equipped with a naturally aspirated engine) and of a newer generation, including downsized (and turbocharged) engines. Tests in each group were carried out under repeatable conditions on a chassis-load dynamometer. The vibrations were measured using single-axis accelerometers mounted on the steering wheel, engine, and driver’s head restraint mounting. The primary purpose of the study was to verify whether the new generations of vehicles equipped with additional high-speed elements (compressors) generate additional harmonics (especially those within the range potentially affecting travel comfort and human health) and whether there are significant changes in the distribution of spectral power density in the new generations. As the study showed, new generations of vehicles are characterized by a different vibroacoustic response, and the trend of change is the same in each of the families studied.

Nonlinear Transient Response of a High Speed Driven Valve System and Stresses in Valve Springs for Internal Combustion Engines

1989 ◽  
Vol 111 (3) ◽  
pp. 264-271 ◽  
Author(s):  
K. Nagaya
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Three Dimensional ◽  
Beam Theory ◽  
Internal Combustion ◽  
Valve Train ◽  
Combination Method ◽  
Combustion Engines ◽  
Valve System ◽  
Cam Profile

This paper presents a method for solving the dynamic response problems of a driven valve system and the stress problem of valve springs for internal combustion engines. In this system there is hysteresis behavior in the spring constants during the rotation of the cam shaft. To treat this nonlinearity, the rigidity of each section is assumed to be one of a partly linear spring. For the valve trains, the cam profile is complex in general. To treat a general cam profile, this paper applies a combination method of the Fourier expansion, the Laplace transform and the analytical connection methods, and gives a response of valve trains. This paper also presents a theoretical result for the stresses in the valve spring due to the motion of the valve train based on the three dimensional curved beam theory.

scholarly journals A zonal approach for estimating pressure ratio at compressor extreme off-design conditions

2018 ◽  
Vol 20 (4) ◽  
pp. 393-404 ◽  
Author(s):  
José Galindo ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Daniel Tarí ◽  
Hadi Tartoussi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Pressure Ratio ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
One Dimensional ◽  
Performance Map

Zero-dimensional/one-dimensional computational fluid dynamics codes are used to simulate the performance of complete internal combustion engines. In such codes, the operation of a turbocharger compressor is usually addressed employing its performance map. However, simulation of engine transients may drive the compressor to work at operating conditions outside the region provided by the manufacturer map. Therefore, a method is required to extrapolate the performance map to extended off-design conditions. This work examines several extrapolating methods at the different off-design regions, namely, low-pressure ratio zone, low-speed zone and high-speed zone. The accuracy of the methods is assessed with the aid of compressor extreme off-design measurements. In this way, the best method is selected for each region and the manufacturer map is used in design conditions, resulting in a zonal extrapolating approach aiming to preserve accuracy. The transitions between extrapolated zones are corrected, avoiding discontinuities and instabilities.

Numerical and experimental investigation of flow phenomena in rotating step-holes for direct-spray-cooled electric motors

2020 ◽  
pp. 146808742091804
Author(s):  
Christopher Beck ◽  
Jürgen Schorr ◽  
Harald Echtle ◽  
Jasmin Verhagen ◽  
Annette Jooss ◽  
...  
Keyword(s):  
Flow Rate ◽  
Electric Motor ◽  
Rotational Speed ◽  
High Speed ◽  
High Efficiency ◽  
Volumetric Flow Rate ◽  
Dielectric Fluid ◽  
Electric Motors ◽  
Test Environment ◽  
Operating Points

Despite their high efficiency, electric motors are thermally limited in some operating points by several types of losses. Whenever temperature–critical components threaten to overheat, the performance is reduced for component protection (derating). The use of a suitable cooling concept may reduce the derating. The design of efficient cooling concepts of electric motors in traction drives with increased power densities is challenging, caused by the fact that the heat releases in the components vary considerably with the operating point. One option to reduce the temperatures is to place the heat sinks close to heat sources. Therefore, direct spray cooling with nozzles located in the rotor shaft is often used for cooling the end windings. The dielectric fluid (e.g. oil) is introduced into the mainly air-filled interior of the electric motor. In the following study, the behavior of the jet in the rotating step-holes at different volumetric flow rates is examined. To carry out the investigation, a new test rig and a novel optically accessible electric motor were designed. In this specifically designed test environment, the shape of the jets of different operating points is investigated by direct high-speed visualization. The cinematography setup is made of a four-light-emitting diode system in combination with a high-speed camera. A combined approach of experiment and simulation is used to find basic mechanisms of spray formation produced by rotating step-holes. Depending on the volumetric flow rate and the rotational speed, the direction of the oil jet gets more curved in relation to the rotating nozzle after exiting the small bore. If the deflection is large, the jet impinges on the wall of the large bore before reaching the end of the nozzle. The jet formation at the exit of the step-hole is mainly driven by the divergent forces in the liquid caused by impingement and the counteracting Coriolis force. Depending on the volumetric flow rate with constant rotational speed, different cross-sectional shapes of the jet at the exit are observed. These characteristic shapes can be grouped as a round undisturbed jet, strands with a connecting lamella and a C-shaped cross-section.

Second Paper: The M.I.R.A. Cross-Wind Generator

1973 ◽  
Vol 187 (1) ◽  
pp. 348-353
Author(s):  
M. J. Rose
Keyword(s):  
Gas Turbine ◽  
Rise Time ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Power Source ◽  
Combustion Engines ◽  
Electric Motors ◽  
Turbine Engine ◽  
Transient Forces ◽  
Natural Wind

The response of vehicles to the transient forces associated with gusting of the natural wind is assuming greater prominence. Total reliance upon natural gusts is unsatisfactory since these are unpredictable and unrepeatable. Major Continental manufacturers have for several years utilized gusts produced by multiple-fan installations, the power source being either electric motors or internal-combustion engines. The M.I.R.A. equipment is centred on a single Rolls-Royce Avon gas-turbine engine, the exhaust gases from which are directed across a roadway. Measurements have indicated that the gust profiles are similar to those encountered on motorways in respect of rise-time.

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