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[ES] En este trabajo el alumno realizará un estudio del sistema de admisión del aire del motor de combustión interna del vehículo de bajo consumo de la Shell Eco-Marathon, haciendo hincapié en que se suministre aire en las mejores condiciones posibles para el motor, se diseñará la geometría del conducto para mejorar el llenado de la cámara de combustión y se simulará el flujo de ese conducto. Se fabricará el conducto en impresión 3D para su implementación y ensayo. El trabajo tendrá la siguiente estructura: 1.- Introducción a la competición Shell Eco-Marathon 2.- Estado del arte 3.- Objetivos del trabajo 4.- Diseño del conducto 5.- Simulación del flujo en software CFD 6.- Fabricación del conducto por impresión 5.- Ensayo del conducto en banco de potencia 6.- Resultados y Conclusiones, [CA] Es considera que l'admissió d'aire d'un vehicle és un sistema de gran rellevància que està infravalorat dins de la competència Shell Eco-Marathon, per la qual cosa l'anàlisi, estudi i disseny de la implantació d'un d'aquests es valora com a digne de realitzar per a un document de l'índole d'un treball de fi de grau. A continuació, es mostrarà el procés de desenvolupament d'un d'aquests sistemes i el pensament darrere d'aquest, explicant els fenòmens involucrats que afecten el seu disseny i com aprofitar-los, de tal manera que s'aconseguisca millorar el comportament d'un vehicle de baix consum. Tot això dut a terme gràcies a dos pilars de l'enginyeria contemporània, que són les eines de simulació i modelatge 3D., [EN] A vehicle’s air intake is considered a highly relevant system that is undervalued within the Shell Eco-Marathon competition, so the analysis, study and design of the implementation of one of these is valued as worthy of carrying out for a document from the nature of a Final Degree Project. On the following pages, the development process of one of these systems and the thinking behind it will be shown, explaining the phenomena involved that affect its design and how to take advantage of it, in such a way that it improves the behavior of a vehicle’s fuel efficiency. All of this was carried out thanks to two pillars of contemporary engineering, which are 3D modeling and simulation tools.

This paper presents the performance of the solid-oxide fuel cell/gas turbine hybrid power generation system with heat recovery waste unit based on the energy and exergy analyses. The effect of air inlet temperature and air/fuel ratio on exergy destruction and network output is determined. For the numerical calculations, air inlet temperature and air fuel ratio are increased from 273 to 373 K and from 40 to 60, respectively. The results of the numerical calculations bring out that total exergy destruction quantity increases with the increase of air inlet temperature and air/fuel ratio. Furthermore, the maximum system overall first and second law efficiencies are obtained in the cases of air inlet temperature and air/fuel ratio equal to 273 K and 60, respectively, and these values are 62.09% and 54.91%. © 2017 Taylor & Francis Group, LLC.

It is known that the thermal and mechanical characteristics of the air flow in the output channel of a turbocharger compressor largely determine the effectiveness of the gas exchange processes quality of a piston engine. The studies were carried out on an experimental installation containing a turbocharger, output channels of different configurations, a measuring base, and a data collection system. It was found that stabilization of the flow in the compressor output channel leads to a significant increase in heat transfer intensity (up to 25 %) compared to the baseline pipeline while simultaneously reducing the turbulence number by up to 30 %. A more significant increase in heat transfer intensity (up to 30 %) was observed in the output channel of the compressor with grooves compared to the base channel while simultaneously increasing the turbulence number by up to 12 %. The proposed configuration of the output channels of the compressor can be used to intensify heat transfer for the natural cooling of the air during the intake process. The configuration with a leveling grid can be used to stabilize the gas-dynamic flow parameters in order to reduce the hydraulic resistance of the intake system of a turbocharged engine. © Published under licence by IOP Publishing Ltd. Russian Science Foundation, RSF: 18-79-10003 The work has been supported by the Russian Science Foundation (grant No. 18-79-10003).

One of the pending issues regarding Homogeneous Charge Compression Ignition (HCCI) engines is high load operation limit constrained by excessive pressure rise rates (PRRs). The present study investigates various measures to reduce combustion harness in a residual-affected HCCI engine. At the same time, the impact of those measures on efficiency and emissions is assessed. Experimental research was performed on a single cylinder engine equipped with a fully-flexible valvetrain mechanism and direct gasoline injection. The HCCI combustion mode with exhaust gas trapping was realized using negative valve overlap and fuel reforming, achieved via the injection of a portion of fuel during exhaust re-compression. Three measures are investigated for the PRR control under the same reference operating conditions, namely: (i) variable intake and exhaust valve timing, (ii) boost pressure adjustment and (iii) split fuel injection to control the amount of fuel injected for reforming. Variable exhaust valve timing enabled control of the amount of trapped residuals, and thus of the compression temperature. The reduction in the amount of trapped residuals, at elevated engine load, delays auto-ignition, which results in a simultaneous reduction of pressure rise rates and nitrogen oxides emissions. The effects of intake valve timing are much more complex, because they include the variability in the amount of intake air, the thermodynamic compression ratio as well as the in-cylinder fluid flow. It was found, however, that both early and late intake valve openings delay auto-ignition and prolong combustion. Additionally, the reduction of the amount of fuel injected during exhaust re-compression further delays combustion and reduces combustion rates. Intake pressure reduction has by far the largest effect on peak pressure reduction yet is connected with excessive NOx emissions. The research successfully identifies air-path and injection techniques, which allow for the control of combustion rates and emissions under elevated load regime, thus shorting the gap towards the real-world application of HCCI concepts.

6th International Conference on Progress in Hydrogen Production and Applications (ICH2P), WOS: 000376695800066, Main objective of this study is to compare performance and emission characteristics of a pilot injection diesel engine with the additions of alternative fuels like pure hydrogen, HHO and biodiesel. In order to achieve this goal, Helianthus annuus (sunflower) biodiesel was produced and blended with volumetric ratio of 10% with diesel fuel. Additionally, intake air was enriched with pure hydrogen or HHO via intake manifold without any structural changes except reduction of injected diesel fuel on the 3.6 L, four cylinders, four stroke diesel engines. Amount of Hydrogen fuel supplied to the engine was adjusted to constant 10 L/min during the experiments. The effects of pure hydrogen and HHO usage with the addition of biodiesel to the engine performance values (Brake Torque, Brake Power and Brake Specific Fuel Consumption) and exhaust emission values (NOx, CO2, CO) were investigated in between 1200 and 2600 rpm engine speeds. Engine performance values were increased with the enriching the intake air with HHO than pure hydrogen compared to the standard diesel fuel operating condition. On the other hand, in terms of exhaust gas emissions, pure hydrogen provided better results than HHO. In both cases, changes on the engine performance results were minimal however improvements on exhaust gas emissions were very promising. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

6th International Conference on Progress in Hydrogen Production and Applications (ICH2P), WOS: 000376695800067, In this experimental study, Hydroxy (HHO; Oxy-hydrogen) - CNG (Compressed Natural Gas) fuel mixtures were used as an additional fuels in a non-modified diesel engine via intake manifold by substitution of diesel fuel. Three cases of experiment performed in a 3.6 L, four cylinders, four stroke diesel engine; first case is non-substitute liquid fuel, neat diesel operation; second case is HHO (5.1 lpm) addition to air mixture and operated under substituted diesel engine and third case is 25HHO-CNG mixture (25% Hydroxy-75% CNG-(5.1-15.3 lpm)) inducted the intake manifold and running with substituted diesel engine. During the tests stepping motor and driver used on fuel pump plunger to substitute diesel fuel as similar to pilot diesel injection. The effects of HHO and HHOCNG fuels relative to neat diesel operations were investigated in between 1200 and 2600 rpm engine speeds and expressed on both engine performance values like; brake torque, brake power, brake specific fuel consumption and brake thermal efficiency; and exhaust emissions; NOx, CO2, CO and exhaust gas temperature (EGT). Results showed that the addition of HHO-CNG mixture is most effective in improving the engine performance and providing more environmentally friendly attitude on exhaust emissions compared to neat diesel operations. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

WOS: 000370306300103, Pilot diesel injection phenomenon consisted by gaseous fuels such as hydrogen and natural gas; ensure the way of exert fuels without any structural modification in compression ignition engines. This study investigates of using 30HCNG (Hydrogenated Compressed Natural Gas) fuel mixture on a non-modified diesel engine operated with diesel fuel replacement rate experimentally. HCNG was used as an additional fuel with air fumigation in a non-modified diesel engine via intake manifold and reduction of diesel fuel by dint of pilot injection. Reduction of diesel fuel was prepared as two different substitutions like 25 and 50% diesel replacement rates controlled by stepping motor devices. 30% Hydrogen and 70% CNG (Compressed Natural Gas) (by volumes) fuel mixture were tested in a 3.6 L, four cylinders, four stroke and water coolant diesel test engine between 1200 and 2600 rpms. Effects of these two different diesel reductions on engine performance and exhaust emissions parameters were compared and illustrated with graphics as brake power, brake torque, and brake specific fuel consumption; CO, CO2 and NOx. Brake thermal efficiency and a minor cost analyses were also performed. It was observed that, 30HCNG fuel mixture with 50% diesel replacement rate affect the engine performance as brake torque, brake power and BSCF values were decreased 4.3%, 8%, 26.8% respectively. Exhaust emission values of NOx and CO2 were decreased 47.2%, 16.7% respectively; however CO emission values were increased 8%. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved., TUBITAK (The Scientific and Technological Research Council of TURKEY) [114M798], This work is a part of a project under grant number "114M798" which is supported and funding by TUBITAK (The Scientific and Technological Research Council of TURKEY).

Gas-dynamic perfection and intensity of heat exchange of intake systems determine the efficiency of the piston engine. The results of numerical simulation and experimental study of the heat transfer of gas streams in the intake system of engines having different configurations are presented in the article. Methods of modeling, experimental setup, geometric configuration of pipelines and measuring base are described in the paper. The investigations were carried out under steady-state air flow in the system. The results of mathematical modeling were verified using experimental studies. It is established that the use of profiled sections in the intake system leads to a decrease in the heat transfer rate up to 20 % at low air flow rates (up to 40 m/s) and an increase in the heat transfer rate up to 9 % at high speeds. © Published under licence by IOP Publishing Ltd. The work has been supported by the Russian Science Foundation (grant No. 18-79-10003).

One of the pending issues regarding Homogeneous Charge Compression Ignition (HCCI) engines is high load operation limit constrained by excessive pressure rise rates (PRRs). The present study investigates various measures to reduce combustion harness in a residual-affected HCCI engine. At the same time, the impact of those measures on efficiency and emissions is assessed. Experimental research was performed on a single cylinder engine equipped with a fully-flexible valvetrain mechanism and direct gasoline injection. The HCCI combustion mode with exhaust gas trapping was realized using negative valve overlap and fuel reforming, achieved via the injection of a portion of fuel during exhaust re-compression. Three measures are investigated for the PRR control under the same reference operating conditions, namely: (i) variable intake and exhaust valve timing, (ii) boost pressure adjustment and (iii) split fuel injection to control the amount of fuel injected for reforming. Variable exhaust valve timing enabled control of the amount of trapped residuals, and thus of the compression temperature. The reduction in the amount of trapped residuals, at elevated engine load, delays auto-ignition, which results in a simultaneous reduction of pressure rise rates and nitrogen oxides emissions. The effects of intake valve timing are much more complex, because they include the variability in the amount of intake air, the thermodynamic compression ratio as well as the in-cylinder fluid flow. It was found, however, that both early and late intake valve openings delay auto-ignition and prolong combustion. Additionally, the reduction of the amount of fuel injected during exhaust re-compression further delays combustion and reduces combustion rates. Intake pressure reduction has by far the largest effect on peak pressure reduction yet is connected with excessive NOX emissions. The research successfully identifies air-path and injection techniques, which allow for the control of combustion rates and emissions under elevated load regime, thus shorting the gap towards the real-world application of HCCI concepts.

The improvement of work processes of piston engines to boost the technical and economic parameters is the main objective in the field of power engineering. The improvement of the gas exchange processes (intake and exhaust processes) quality is one of the possible profiles to improve the efficiency and reliability of piston internal combustion engines. The study of the instantaneous local heat transfer at flow unsteadiness is one of the objectives of the experimental studies of the thermomechanical processes in the intake and exhaust systems of the engines. The influence of configuration of the intake and exhaust pipes on the heat transfer intensity is a relevant engineering problem. The local heat transfer intensity data serves as the basis to determine the basis for determination of heating of the air (at intake), cooling exhaust gas (at exhaust), calculation of thermal stresses in the nodes and details of intake and exhaust systems. The article presents the results of the experimental investigation of the instantaneous local heat transfer (taking into account the hydrodynamic nonstationarity) in the intake and exhaust pipes of different configurations for piston internal combustion engines. It is established that the cross profiling of the intake and exhaust pipes of piston engines leads to 5-20% decrease in the local heat transfer intensity depending on the crankshaft speed. © 2017 The Authors. Published by Elsevier Ltd. The reported study was funded by FBR R according to the research project

This paper reports 1D and 3D CFD analyses aiming to improve the gas-dynamic noise emission of a downsized turbocharged VVA engine through the re-design of the intake air-box device, consisting in the introduction of external or internal resonators. Nowadays, modern spark-ignition (SI) engines show more and more complex architectures that, while improving the brake specific fuel consumption (BSFC), may be responsible for the increased noise radiation at the engine intake mouth. In particular VVA systems allow for the actuation of advanced valve strategies that provide a reduction in the BSFC at part load operations thanks to the intake line de-throttling. In these conditions, due to a less effective attenuation of the pressure waves that travel along the intake system, VVA engines produce higher gas-dynamic noise levels. The worsening of the engine gas-dynamic performance can be compensated with a partial re-design of the air-box device, without significantly penalizing the engine power output. In order to find new design configurations of the air-box device capable of improving the noise levels, different numerical models can be successfully employed. In the present work, a detailed 1D engine model is firstly developed and validated against the experimental data at full load operations. 1D model is realized within GT-Power(TM) software and it utilizes proper user routines for the modeling of the turbulence and combustion process and for the handling of different intake valve strategies. The 1D engine model also includes a refined user model of the turbocharger able to better describe the acoustic behavior of the device. The engine model allows for the prediction of the main overall engine performances and the gas-dynamic noise with good accuracy. It also provides a first estimation of the gas-dynamic noise and gives reliable boundary conditions for the subsequent unsteady 3D CFD analyses, allowing to obtain a more accurate noise prediction. A proper Helmholtz resonator is designed and virtually installed along the inlet pipe of the air-box device. An additional geometrical configuration of the air-filter box, that includes an internal resonator, obtained through the insertion of inner walls, is considered, too. The effectiveness of the redesigned air-box configurations, are firstly tested in terms of Transmission Loss characteristics, and in terms of gasdynamic noise abatement, as well.

In this study, the effects of residual gas fraction (RGF) on homogeneous charged compression ignition (HCCI) combustion were investigated experimentally. Experiments were performed at different lambda values and constant intake air temperature of 80 degrees C with the blend of 20% n-heptane and 80% isooctane (PRF80) test fuel. In order to obtain exhaust gas trapping and HCCI operation, two different cam mechanisms, having reduced valve lift, were used. Valve lift values of 5.5 mm (In5.5) and 3.5 mm (In3.5) were used in cam mechanisms. Exhaust valve lift values were 3.5 mm (Ex3.5) for both cam mechanisms. The experimental findings showed that in-cylinder pressure and heat release rate decreased using In5.5-Ex3.5 cam mechanism compared to In3.5-Ex3.5. More residual gases were trapped using In3.5-Ex3.5 cam mechanism. Combustion was also retarded with low lift cams due to more trapped residual gases. Indicated thermal efficiency was found 28.4% with In 3.5-Ex 3.5 whereas obtained 33.57% with In 5.5-Ex 3.5 cam mechanism at 1000 rpm. RGF was computed as 20.12% and 21.12% with In 5.5-Ex 3.5 and In 3.5 Ex 3.5 cam mechanisms, respectively, at 1000 rpm engine speed and stoichiometric air/fuel ratio. Moreover, indicated thermal efficiency was found to be higher about 17.91% with In 5.5-Ex 3.5 according to In 3.5 Ex 3.5 at 1200 rpm. Consequently, it was observed that HCCI combustion phasing can be controlled using low lift cams. It was seen that trapping exhaust gases in the cylinder is a feasible and practical method to control combustion phasing and spread out the HCCI operating range. In addition, stable HCCI combustion can be achieved trapping exhaust gases resulting in avoiding knocking especially at high engine loads. (C) 2016 Elsevier Ltd. All rights reserved.

[EN] The present study tries to be a contribution for the development of more precise theoretical models for predicting the dissipation of heat through the combustion chamber walls of reciprocating (internal combustion) IC engines. A fast response thermocouple was embedded in the combustion chamber of a single cylinder engine to measure instantaneous wall temperatures. The heat flux was obtained by solving the one-dimensional transient energy equation with transient boundary conditions using the Fast Fourier Transform. The engine was tested under different operating conditions to evaluate the sensitivity of the measurement procedure to variations of three relevant combustion parameters: injection pressure, air temperature and oxygen concentration at the intake. The local heat flux obtained was compared with other relevant parameters that characterize the thermal behaviour of engines, showing, in most of the cases, correlation among them. The results showed that the instantaneous heat flux through the walls and hence the local wall temperatures are strongly affected by the ignition delay and the start of combustion. © 2010 Elsevier Ltd.

Aerodynamic characteristics of helicopter engine side air intakes are investigated. The experimental data set is obtained by wind tunnel testing of a full-scale helicopter fuselage section model. For the simulation of realistic engine operation, engine mass flow rates are reproduced. Five-hole pressure probe data of the aerodynamic interface plane as well as local surface pressure distributions are compared for different geometries and operation conditions. Previous investigations indicate that unshielded, sideways-facing air intakes yield lowest distortion and highest total pressure levels in low speed conditions. In fast forward flight condition, however, forward-facing intake shapes are more beneficial. On this basis, the current research assesses the optimization potential of retrofit modifications such as a rear spoiler (small scoop) and an intake guide vane. Two optimal configurations of retrofit modifications are identified, combining benefits of the various basic intake and plenum chamber shapes.

Many theoretical studies have shown the existence of a hysteresis effect in the solution of oblique shock reflections. In fact, a wide domain of free-stream Mach number and shock angle values exists where regular reflection and Mach reflection are both possible solutions for the same flow conditions. Part of this domain overlaps the typical operating conditions of supersonic air intakes, and therefore it is of practical interest to obtain a deeper understanding of the theoretical problem. Indeed, although both solutions are theoretically possible, they yield very different flowfields and consequently large discrepancies in the evaluation of the air intake performance. Numerical solutions for steady configurations have been carried out and compared with the flow evolution obtained for time-dependent cases. The results have confirmed numerically the existence of the multiple solution domain where hysteresis takes place in time-dependent simulations. The analysis of the physical and numerical problems encountered has provided indications for a correct simulation in practical applications.

The strong competition between the leading civil aircraft manufacturers Boeing and Airbus and new economical and ecological constraints have lead to new aircraft concepts and to a change of the aircraft architecture design. In particular the bleedless architecture of the more electrical aircraft promises new optimization potential. However, in the conventional aircraft architecture bleed air is generated by the compressor of the engines, in the more electrical aircraft architecture the lack of bleed air has to be compensated by additionally inducted air. Furthermore, when taking into account that the conventional centralized hydraulic system shall also be replaced by electrical actuators or local hydraulic units, then, more additional cooling air from the outside atmosphere has to be inducted to fulll the new additional cooling requirements of the equipment. The higher amount of required fresh and cooling air can only be provided by either additional air intakes or up-scaled air intakes. Both approaches have a crucial effect on the overall efficiency of the aircraft in particular in regard to the additional produced drag of the new or up-scaled air intakes. Even in the early design phase of the aircraft the air intake type has to be specified, and details of the geometrical design and the placement of air intakes have to be fixed. However, a design freeze is only possible when sophisticated evaluation techniques have been applied which guarantuee for certain intake types optimal positions in regard to performance and integration. Only then an efficiency benefit in comparison to conventional aircraft architecture can be obtained. Nevertheless, constraints might inhibit proposed locations, which, in fact, means taking into account performance losses on the air intake side. Therefore, further optimization potential has to be opened i.e. by using additional ow manipulating devices in combination with the chosen air intake. Thus, the main objective of the presented research work is to evaluate the potential of vortex generators for the enhancement of the efficiency of air intakes. In the presented work essential aspects of the air-intake design and the effect of vortex generators on the ow eld will be discussed. In particular constraints which lead to a decision for a NACA air-intake type and a certain combinations of vortex-generators will be explained. One goal of the work is to demonstrate that it is possible to use state of the art grid deformation techniques to improve the performance of such a complex aircraft system. Hereto, two congurations will be considered, one is a wind tunnel configuration, the other is an A340 like DLR F12 aircraft configuration. Results of CFD simulations for the air-intake and vortex-generator combinations will be shown and discussed. Associated fl ow phenomena will be visualized and analyzed. Finally based on the CFD results suitable vortex-generator and air-intake combinations will be evaluated and compared.

Two research institutes TNO Defence, Security and Safety and DRDC-Valcartier have worked together on the improvement of modeling and simulation tools for the functioning of supersonic air intakes for realistic ramjet engines of tactical missiles. The emphasis laid on complex rectangular intake designs making use of an internal bleed system and on incorporating the functioning of air intakes at off-design conditions (below and above the design Mach number and at angle-of-attack with respect to the freestream velocity). In order to generate air intake performance data validated CFD-strategies were pursued. Two-and three dimensional CFD studies were performed and in order to validate the numerical results, a wind tunnel test campaign was conducted. The understanding of ramjet air intakes was greatly enhanced over the years and validated numerical approaches were successfully obtained. Furthermore insight in the influence on the availability of accurate intake performance data on ramjet engine and missile performance levels was gained. © 2009 by TNO Defence, Security and Safety.

Two research institutes TNO Defence, Security and Safety and DRDC-Valcartier have worked together on the improvement of modeling and simulation tools for the functioning of supersonic air intakes for realistic ramjet engines of tactical missiles. The emphasis laid on complex rectangular intake designs making use of an internal bleed system and on incorporating the functioning of air intakes at off-design conditions (below and above the design Mach number and at angle-of-attack with respect to the freestream velocity). In order to generate air intake performance data validated CFD-strategies were pursued. Two-and three dimensional CFD studies were performed and in order to validate the numerical results, a wind tunnel test campaign was conducted. The understanding of ramjet air intakes was greatly enhanced over the years and validated numerical approaches were successfully obtained. Furthermore insight in the influence on the availability of accurate intake performance data on ramjet engine and missile performance levels was gained. © 2009 by TNO Defence, Security and Safety.

The numerical simulation of an integrated, liquid-fuelled ramjet engine comprising supersonic air intake, subsonic combustor and a convergent-divergent nozzle has been carried out and the results are discussed in this paper. These results include cold flow studies, heat addition in the combustor and full engine analysis with coupled simulation of supersonic air-intake and combustion chamber along with the nozzle. Overall ramjet operation depends on the performance of the air intake and the combustion chamber. The coupling phenomena are very dominant and performance of air intake is affected vastly by the combustor operation and vice versa. In this paper, a numerical analysis of integrated liquid ramjet engine considering coupling phenomena between various sub-systems viz., air intake, combustor and nozzle has been reported. � 2008, DESIDOC.

Ramjet propulsion is often proposed for airbreathing applications with speeds higher than Mach 3. However, for speeds higher than Mach 5, the performance of a ramjet drops significantly and the scramjet is the preferred option. The shock-induced combustion ramjet, or shcramjet, is also an interesting alternative at higher flight speeds. Its configuration differs significantly from the scramjet with a longer intake to provide for fuel injection and evaporation while maintaining a lower air temperature to prevent ignition of the flammable mixture with a slower pressure recovery. A detonation wave completes the pressure recovery and ensures ignition of the air-fuel mixture upon reaching the combustion chamber. This longer intake, necessary for adequate air and fuel mixing, can be combined with a much shorter combustion section. Overall, when the entire vehicle is considered, the shcramjet may result in improved performance for the same mission over the scramjet-powered vehicle. To complete a preliminary design of scramjet and shcramjet vehicles powered at hypersonic speeds, an on-design computational tool was developed to optimize their configurations and compare various performance parameters as a function of Mach number in the range from 7 to 12. In order to compare common baselines for the scramjet and the shcramjet, a configuration was chosen with a mass limited to 430 kg for validation with other design tools. Eventually the configurations were optimized for a balance between the thrust-drag and lift-weight forces by tailoring the external geometry and configuring the internal components to offer the best performance for both vehicles. Since a mixing submodel with not yet available to interact with the other submodels, the various performance parameters were calculated and presented graphically for constant combustion efficiency values. Ultimately both configurations give approximately the same performance when compared with the same combustion efficiency. The resulting hypersonic shapes are presented with detailed explanations of their on-design configurations as the Mach number is varied from 7 to 12. © 2008 by the Department of National Defence and Université.

Ramjet propulsion is often proposed for airbreathing applications with speeds higher than Mach 3. However, for speeds higher than Mach 5, the performance of a ramjet drops significantly and the scramjet is the preferred option. The shock-induced combustion ramjet, or shcramjet, is also an interesting alternative at higher flight speeds. Its configuration differs significantly from the scramjet with a longer intake to provide for fuel injection and evaporation while maintaining a lower air temperature to prevent ignition of the flammable mixture with a slower pressure recovery. A detonation wave completes the pressure recovery and ensures ignition of the air-fuel mixture upon reaching the combustion chamber. This longer intake, necessary for adequate air and fuel mixing, can be combined with a much shorter combustion section. Overall, when the entire vehicle is considered, the shcramjet may result in improved performance for the same mission over the scramjet-powered vehicle. To complete a preliminary design of scramjet and shcramjet vehicles powered at hypersonic speeds, an on-design computational tool was developed to optimize their configurations and compare various performance parameters as a function of Mach number in the range from 7 to 12. In order to compare common baselines for the scramjet and the shcramjet, a configuration was chosen with a mass limited to 430 kg for validation with other design tools. Eventually the configurations were optimized for a balance between the thrust-drag and lift-weight forces by tailoring the external geometry and configuring the internal components to offer the best performance for both vehicles. Since a mixing submodel with not yet available to interact with the other submodels, the various performance parameters were calculated and presented graphically for constant combustion efficiency values. Ultimately both configurations give approximately the same performance when compared with the same combustion efficiency. The resulting hypersonic shapes are presented with detailed explanations of their on-design configurations as the Mach number is varied from 7 to 12. © 2008 by the Department of National Defence and Université.

Tutkimuksessa selvitettiin 1950-1960 ja 1970 -luvun asuinkerrostalon ilmanvaihdon tämän hetkinen toiminta sekä mittauksin että asukashaastatteluin. Rakennuksille on ehdotettu ilman vaihdon korjausratkaisuja, jotka soveltuvat suureen osaan asuntokantaa. Painovoimaisen ilmanvaihdon korjausvaihtoehtojen toimivuutta vuositasolla tarkasteltiin myös laskelmin. Suuri osa asukkaista haluaa itse säätää ilmanvaihtoa, joten korjauksessa pitäisi pyrkiä ilman vaihdon tarpeenmukaiseen ohjaukseen. Se voidaan toteuttaa koneellisessa ilmanvaihdossa venttiiliohjauksella tai huoneistokohtaisilla ilmanvaihtokoneilla. Painovoimaisen ilmanvaihdon toimintaa voidaan parantaa ulkolämpötilan mukaan säätyvillä venttiileillä.