Aerospace Inventics Visual Guide

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A colection of my early engine designs as an aerospace engineering student.


Aerospace inventics-visual guideValeriu DrganBucharest 2010ISBN:978-973-0-09403-92foreword The things that are truly important in life are not the ones nobody has done before but the ones that everyone needs to do. Simplification is one of the most difficult things to do. Thats why the ability to think in a simple way is so important. 34Contents Rotary engines Steam engines The plano-reactor The X-Mass tree turboprop The dual core turbofan Some history The turbo-helix Magnetic non-contact cogged wheels Sketches for magnetic gearing Unconventional compressor turbofan engines This is invisible Micro-UAV concept Other studies stealth jet trainer Supercirculation hovering stealth aircraft study A modular centrifugal compressor study Two stage centrifugal compressor study The wind milling enginealso known as theRam Turbine Engine Another perspective Other variations on the ram turbojet -the gyrocopter study -the anemometric turbo-jet configurations -the slim, variable pitch ram air turbine jet engine The MAMuT Taking the MAMuT one step further5contents A fluid gyroscope Tip jet evolution Tip jet studies Micro-turbine propeller Hydrogen peroxide power plant Nuclear Turbofans SANDRa Stator heat exchangers for advanced cycle turbofan engines From A to C trough B.5 The cube The cuboid engine with hyper modularity In operation Other considerations regarding the cuboid engine Tip compressor turbofan study The semi-pressurized burner turbofan Supercirculation vs. countercirculation The Maximal Attitude Immediate Response Actuator The Rhino Chevron and diamond canards The negative delta wing and diamond canards The ways conventional wings and Delta wings produce lift The negative delta Diamond canards On their ownand on the aircraft67Rotary enginesWhen it comes to internal combustion engines, rotary engines are definitely the Superstars.Their fascinating appearance, with outlandish geometry and kinematic is also doubled by the incredible power output of these machines .One of my early design concepts regarding a centered rotary body as opposed to the Wankeleccentric rotor. The idea was that a centered rotor can spin at higher rpm than an eccentric one.8The design evolved into the one below, the pictures shows the two important phases of its operation: First: At 6oclock-admissionAt 9oclock preparing for compressionAt 3oclock- preparing for complete exhaustSecond: At 6oclock-admission-endingAt 9oclock compression-ignitionAt 3oclock- complete exhaustCompressor rockerAdmission sectionExhaust rocker with micro-valve 9Another rotary piston engine design, based on the same belief that a centered rotor is faster than an eccentric one which would yield more explosions per second and thus prove to be more powerful. Also an advantage of having higher rpm is the possibility of use in moto-reactors in which the compressor is spanned by the piston engine and not by a turbine-in fact Henri Coand made the first jet engine using this principle 1910 Paris air show.10A more far-fetched rotary engine design, a bit more simple with fewer moving parts but also with a higher volume (which is a bit of a drawback). Observe not only the geometry of the engine but also the two linkage methods used between individual pistons:Up: the second piston is rotated 180 to the firstDown: the second piston is mirrored ,(the same two linking methods are used for the previous one).1112Steam engines The steam engine has been at the forefront of engineering for decades, most early brilliant engineers derived theories and developed outstandingly complex machines. As a measure of relevance, the Wankel engine a lot of people praise had a steam cousin. The rotor geometry was the same Reuleaux triangle and the chamber was quite similar in shape too. Of course it only worked by extracting work from the steam and not by compressing and igniting mixtures of air and petrol but the point is that if its mechanical complexity and ingenuity youre after, you should definitely take a look at as much steam engines as possible. Another interesting bit is that George Braytons initial engine worked as an internal combustion engine using only steam engine parts: The compression cylinder, the expansion cylinder and a burner in between. The same principle governs modern day turbine engines only the cylinders are replaced by bladed machinery-which can accommodate a much higher flow of work fluid.13The plano-reactorA jet engine is comprised in its most basic form by a burning chamber and a nozzleFor turbine engines we also add a turbo-compressor, however not all air-breathing jet engines with a kinematic compressor have turbines, a perfect example is the Coanda 1910 which had its centrifugal compressor driven by a piston engine. The picture below depicts my very first jet engine concept : a plano-reactor. Lacking any practical use, you may say I rather designed it than engineered it.14As most readers may already know, a centrifugal compressor s compression ratio depends on both rpm and radius; for aero-engines its obvious that we must keep the radius to the minimum to avoid drag, thus we are faced with a tradeoff : either lower mass flow or lower compression; the plano-reactor tries to eliminate the radius as a limiting factor by placing the compressor on its side. In doing so we cannot use a conventional spool for the turbo-compressor, therefore my solution was a planetary and belt transmission. Also you can see the burning chamber has a split for the two turbine wheels, at that time I considered a separate turbine for the accessory box. Also theres a compressed air manifold for starting the engine.15The X-Mass tree turbopropThis turboprop design wishes to make use of the counter-rotating stage concept. Its been obvious for some time that counter rotating stages are much lighter in terms of mass as they act as each-others stator (however that proves to be quite problematic requiring careful engineering).16The design below can be explained as a counter rotating 4-spool booster that spins on a fixed tube around the free turbine inner spool. intakeStationary tubeOne of the counter-rotating turbo-compressor stagesburnerreductorFree turbine spool going inside the stationary tubeexhaust17The dual core turbofan The dual core concept relies on the counter-rotating turbine/compressor stages on one hand and on the thrust optimization by increasing the core temperature on the other. As it can be seen, it has two burning chambers: one for the counter-rotating turbo-compressors and the other for propulsion. The accessory gearbox gets the power via a heat exchanger at the back of the nozzle. Separating the turbine combustor from the core booster can offer new possibilities for optimization in both engine performance such as thrust or efficiency without having to sacrifice one in favor of the other. It is also a good way to decrease maintenance cost by prolonging the active life of the turbine because the turbine inlet temperature can be lowered. This arrangement is somewhat similar in those aspects with the afterburning turbojet.18 The initial sketch of the dual core turbofan only featured the counter-rotating four stage turbo-compressors and the thrust core chamber19 The later, more elaborated version featured the internal separator lip to vary the mass flow for the turbine burning chamber and the heat exchanger heating circuit for extracting power needed for driving the accessories.Turbine burnerThrust burnerHot circuit for close-circuit generatorTurbinecompressorMass flow regulator lip20Some history In 1906 at Montesson-near Paris, France, Traian Vuiaachieved the first self-powered flight in the history of mankind. This may seem puzzling since we all know the first motorized flight was made by the Wright brothers a few years earlier..true but also a deceptive choice of words: motorized flight-yes, but the liftoff could not be achieved on engine power alone-they were catapulted; the fact that they had an engine on board only prolonged the flight.2122Steam powerVuias engine technology was vapor-based, i.e. the compressed CO2 was decompressed in a piston engine that provided the desired power to weight ratio, a ratio unavailable at that time for the internal combustion engine . The following turbo-helix was developed for air modelers who still use this compressed gas propulsion system23Side and front sections of my vapor based turbo-helixCompressed gas enters trough the central manifold and exits trough mini nozzles on the tip of the blades which spines the propeller.24Magnetic non-contact cogged wheelsThe cogs of the wheels are designed in the same manner (geometrically) as normal however this is because we want to optimize the interaction between them i.e. not to have any vibrations due to in-homogenous interaction25Sketches for magnetic gearing This new gearing system relies on magnetic attraction rather than rejection. Thus it can be made more solid see the asymmetrical gears-so it can take higher loadings. The problem with it is that it can only go in one direction per wheel i.e. each cogged wheel can only be turned in one direction to obtain the non-contact characteristic.NS26Unconventional compressor turbofan engines:The turbofan below dwells on the concept of integrating a centrifugal compressor with another component of a turbine engine, so far Ive seen only one other such example in which the turbine blades were hollow and air from the compressor passed trough their interior and were discharged in the combustor only to be re-passed on the turbine as heated gas. In the drawings below youll see my turbofan model which consists of two counter-rotating centrifugal compressors.27Air (for combustor) enters the engine in the center part trough a conventional centrifugal rotor-the stator of this rotor is actually the interior of the fan blades which is counter rotating-for more compactness. Please note the shrouds on the base and tip of the fan which keep