Simulation of four stroke engine cycle for a 4 - valve pentroof engine in KIVA 3VR2

The main purpose of this project is to understand the process of engine simulation using the open source CFD code called KIVA. This report mainly discusses the simulation of the 4-valve Pentroof engine through KIVA 3VR2. KIVA is an open source FORTRAN code which is used to solve the fluid flow field in the engines with the transient 2D and 3D chemically reactive flow with spray. It also focuses on the complete procedure to simulate an engine cycle starting from pre- processing until the final results. This report will serve a handbook for the using the KIVA code.

NH90 helikopterin moottoreiden syklilaskennan tehostaminen ja elinkaarihallinta

Tutkimustyö liittyy NH90 Helikopterin RTM-322 moottoreiden syklivaihdettavi-en osien huollonsuunnitteluun ja sen kehittämiseen. Tavoitteena oli löytää nykyi-sen käyttösyklilaskennan tilalle säästävämpi ratkaisumalli ja saada määritettyä suihkumoottorin osakokonaisuuksille lisälentoaikaa sekä huollonsuunnitteluun järkevämmät käyttöjaksot. Tähän päästiin selvittämällä käytännön lentotoiminnan avulla uudet laskentakertoimet ja -mallit moottorin eri osien eliniän määrittämi-seksi. Konkreettisena tavoitteena oli saada koneen käyttöhistoriaan perustuen kohdeorganisaatiolle esitys, miten moottoreiden käyttösyklilaskentaa tulisi muut-taa ja tehostaa. Diplomityön aihe muodostuu kolmesta tutkimusongelmakokonaisuudesta; moot-torin käyttöhistorian tutkimisesta, moottorivalmistajan hyväksymien syklilasken-tamenetelmien tutkimisesta ja moottorin syklien säästövaikutustarkastelusta tut-kimuksen määrittämillä uusilla laskentamenetelmillä. Tutkimuksen tuloksena muodostui NH90 huollonsuunnitteluun arvio mahdollisis-ta moottorisyklisäästöistä sekä moottoreiden näkökulmasta priorisoitu lista heli-kopterien moottoreiden laitevaihtohuoltojen järjestyksestä seuraavan viiden vuo-den aikana. Syklien säästötarkastelun pohjalta suoritettiin yhden koneen osalta koko käyttöhistorian ajalta takaisinlaskentatarkastelu. Tutkimuksessa selvitettiin Ilmavoimien meneillään olevien projektien valossa moottorisyklien tarkanlasken-nan toteuttamismahdollisuudet tulevaisuudessa. Tutkimuksessa saatujen tulosten avulla vältyttäisiin tulevaisuudessa RTM-322 moottorin ennenaikaisilta laitevaih-doilta koko NH90 kaluston suhteen ja näin saataisiin aikaan merkittävän suuria säästöjä vuoteen 2020 mennessä.

Avaliação termoanalítica da eficiência de antioxidantes na estabilidade oxidativa do biodiesel de mamona

The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid

Sviluppo di metodologie per la Stima in Tempo Reale delle Grandezze Indicate in Motori a Combustione Interna

Modern Internal Combustion Engines are becoming increasingly complex in terms of their control systems and strategies. The growth of the algorithms’ complexity results in a rise of the number of on-board quantities for control purposes. In order to improve combustion efficiency and, simultaneously, limit the amount of pollutant emissions, the on-board evaluation of two quantities in particular has become essential; namely indicated torque produced by the engine and the angular position where 50% of fuel mass injected over an engine cycle is burned (MFB50). The above mentioned quantities can be evaluated through the measurement of in-cylinder pressure. Nonetheless, at the time being, the installation of in-cylinder pressure sensors on vehicles is extremely uncommon mainly because of measurement reliability and costs. This work illustrates a methodological approach for the estimation of indicated torque and MFB50 that is based on the engine speed fluctuation measurement. This methodology is compatible with the typical on-board application restraints. Moreover, it requires no additional costs since speed can be measured using the system already mounted on the vehicle, which is made of a magnetic pick-up faced to a toothed wheel. The estimation algorithm consists of two main parts: first, the evaluation of indicated torque fluctuation based on speed measurement and secondly, the evaluation of the mean value of the indicated torque (over an engine cycle) and MFB50 by using the relationship with the indicated torque harmonic and other engine quantities. The procedure has been successfully applied to an L4 turbocharged Diesel engine mounted on-board a vehicle.

Implementation of the conjugate heat transfer code in KIVA-4

KIVA is an open Computational Fluid Dynamics (CFD) source code that is capable to compute the transient two and three-dimensional chemically reactive fluid flows with spray. The latest version in the family of KIVA codes is the KIVA-4 which is capable of handling the unstructured mesh. This project focuses on the implementation of the Conjugate Heat Transfer code (CHT) in KIVA-4. The previous version of KIVA code with conjugate heat transfer code has been developed at Michigan Technological University by Egel Urip and is be used in this project. During the first phase of the project, the difference in the code structure between the previous version of KIVA and the KIVA-4 has been studied, which is the most challenging part of the project. The second phase involves the reverse engineering where the CHT code in previous version is extracted and implemented in KIVA-4 according to the new code structure. The validation of the implemented code is performed using a 4-valve Pentroof engine case. A solid cylinder wall has been developed using GRIDGEN which surrounds 3/4th of the engine cylinder and heat transfer to the solid wall during one engine cycle (0-720 Crank Angle Degree) is compared with that of the reference result. The reference results are nothing but the same engine case run in the previous version with the original code developed by Egel. The results of current code are very much comparable to that of the reference results which verifies that successful implementation of the CHT code in KIVA-4.

Implementation of monotonic higher order upwind scheme in KIVA 4

KIVA is a FORTRAN code developed by Los Alamos national lab to simulate complete engine cycle. KIVA is a flow solver code which is used to perform calculation of properties in a fluid flow field. It involves using various numerical schemes and methods to solve the Navier-Stokes equation. This project involves improving the accuracy of one such scheme by upgrading it to a higher order scheme. The numerical scheme to be modified is used in the critical final stage calculation called as rezoning phase. The primitive objective of this project is to implement a higher order numerical scheme, to validate and verify that the new scheme is better than the existing scheme. The latest version of the KIVA family (KIVA 4) is used for implementing the higher order scheme to support handling the unstructured mesh. The code is validated using the traditional shock tube problem and the results are verified to be more accurate than the existing schemes in reference with the analytical result. The convection test is performed to compare the computational accuracy on convective transfer; it is found that the new scheme has less numerical diffusion compared to the existing schemes. A four valve pentroof engine, an example case of KIVA package is used as application to ensure the stability of the scheme in practical application. The results are compared for the temperature profile. In spite of all the positive results, the numerical scheme implemented has a downside of consuming more CPU time for the computational analysis. The detailed comparison is provided. However, in an overview, the implementation of the higher order scheme in the latest code KIVA 4 is verified to be successful and it gives better results than the existing scheme which satisfies the objective of this project.

Aerothermodynamic cycle analysis of a dual-spool, separate-exhaust turbofan engine with an interstage turbine burner

This study focuses on a specific engine, i.e., a dual-spool, separate-flow turbofan engine with an Interstage Turbine Burner (ITB). This conventional turbofan engine has been modified to include a secondary isobaric burner, i.e., ITB, in a transition duct between the high-pressure turbine and the low-pressure turbine. The preliminary design phase for this modified engine starts with the aerothermodynamics cycle analysis is consisting of parametric (i.e., on-design) and performance (i.e., off-design) cycle analyses. In parametric analysis, the modified engine performance parameters are evaluated and compared with baseline engine in terms of design limitation (maximum turbine inlet temperature), flight conditions (such as flight Mach condition, ambient temperature and pressure), and design choices (such as compressor pressure ratio, fan pressure ratio, fan bypass ratio etc.). A turbine cooling model is also included to account for the effect of cooling air on engine performance. The results from the on-design analysis confirmed the advantage of using ITB, i.e., higher specific thrust with small increases in thrust specific fuel consumption, less cooling air, and less NOx production, provided that the main burner exit temperature and ITB exit temperature are properly specified. It is also important to identify the critical ITB temperature, beyond which the ITB is turned off and has no advantage at all. With the encouraging results from parametric cycle analysis, a detailed performance cycle analysis of the identical engine is also conducted for steady-stateengine performance prediction. The results from off-design cycle analysis show that the ITB engine at full throttle setting has enhanced performance over baseline engine. Furthermore, ITB engine operating at partial throttle settings will exhibit higher thrust at lower specific fuel consumption and improved thermal efficiency over the baseline engine. A mission analysis is also presented to predict the fuel consumptions in certain mission phases. Excel macrocode, Visual Basic for Application, and Excel neuron cells are combined to facilitate Excel software to perform these cycle analyses. These user-friendly programs compute and plot the data sequentially without forcing users to open other types of post-processing programs.

IMPACT OF ENGINE CALIBRATION ON PM OXIDATION IN A CATALYZED PARTICULATE FILTER OVER A TRANSIENT CYCLE: A MODELLING STUDY

The combustion strategy in a diesel engine has an impact on the emissions, fuel consumption and the exhaust temperatures. The PM mass retained in the CPF is a function of NO2 and PM concentrations in addition to the exhaust temperatures and the flow rates. Thus the engine combustion strategy affects exhaust characteristics which has an impact on the CPF operation and PM mass retained and oxidized. In this report, a process has been developed to simulate the relationship between engine calibration, performance and HC and PM oxidation in the DOC and CPF respectively. Fuel Rail Pressure (FRP) and Start of Injection (SOI) sweeps were carried out at five steady state engine operating conditions. This data, along with data from a previously carried out surrogate HD-FTP cycle [1], was used to create a transfer function model which estimates the engine out emissions, flow rates, temperatures for varied FRP and SOI over a transient cycle. Four different calibrations (test cases) were considered in this study, which were simulated through the transfer function model and the DOC model [1, 2]. The DOC outputs were then input into a model which simulates the NO2 assisted and thermal PM oxidation inside a CPF. Finally, results were analyzed as to how engine calibration impacts the engine fuel consumption, HC oxidation in the DOC and the PM oxidation in the CPF. Also, active regeneration for various test cases was simulated and a comparative analysis of the fuel penalties involved was carried out.

Numerical Model of a Variable-Combined-Cycle Engine for Dual Subsonic and Supersonic Cruise

Efficient high speed propulsion requires exploiting the cooling capability of the cryogenic fuel in the propulsion cycle. This paper presents the numerical model of a combined cycle engine while in air turbo-rocket configuration. Specific models of the various heat exchanger modules and the turbomachinery elements were developed to represent the physical behavior at off-design operation. The dynamic nature of the model allows the introduction of the engine control logic that limits the operation of certain subcomponents and extends the overall engine operational envelope. The specific impulse and uninstalled thrust are detailed while flying a determined trajectory between Mach 2.5 and 5 for varying throttling levels throughout the operational envelope.

Operator and organizational maintenance manual : generator set, diesel engine, precise power, 100 kw, AC, 120/208V, 240/416V, 3 phase, 60 cycle, at 1800 rpm, 83.3 kw, 120/208V, 240/416V, 3 phase, 50 cycle at 1500 rpm, skid mounted ....

"April 1961."

Operator and organizational maintenance manual (including repair parts and special tool lists) : tester, engine distributor, bench type, 6, 12, and 24-volt distributors, single-phase, 60-cycle, 115-volt (Heyer Products Company Inc., model 168) (4910-392-2939).

"30 September 1963."

Organizational maintenance manual : lathe, engine, bench mounted, solid bed type, 10 inch swing, no. 2 Morse taper center, 1-3/8 spindle hole, 110-volts, 60 cycle, single phase 3/4-horsepower, w/Army dwg. no. 7550151 bench (standard-modern tool series 2,000 model, 11 inch) (3416-517-0955).

"November 1965."

Operator's manual : boring machine, engine cylinder, portable, 3 1/2 to 7 1/2 bore diameter, 18 inch depth of bore, 110-volt, 60-cycle, single-phase (Cedar Rapids Engineering Company model FL) (4910-223-9734).

"November 1965."

Field and depot maintenance manual : generator set, diesel engine precise power; 100 KW, AC, 120/208 V, 240/416 V, 3 phase, 60 cycle at 1800 RPM, 83.3 KW, 120/208 V 240/416 V, 3 phase, 50 cycle at 1500 RPM; skid mounted (Detroit Diesel Divn. General Motors Corp. model 6910A) FSN 6115-798-3444.

Includes index.

Generator set, electric, portable, diesel-driven skid-mounted, 30 KW, 60-cycle, 120/208 or 240/416 volt, 3-phase convertible to 50-cycle, 120/208 or 240/416 volt, 3- phase Stewart and Stevenson model WGD-3012 (less engine) /

Includes index.