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Viewing 1 to 30 of 331
2017-09-04
Technical Paper
2017-24-0020
Michele Becciani, Alessandro Bianchini, Matteo Checcucci, Lorenzo Ferrari, Michele De Luca, Luca Marmorini, Andrea Arnone, Giovanni Ferrara
Abstract The onset of aerodynamic instabilities in proximity of the left margin of the operating curve represents one of the main limitations for centrifugal compressors in turbocharging applications. An anticipated stall/surge onset is indeed particularly detrimental at those high boost pressures that are typical of engine downsizing applications using a turbocharger. Several stabilization techniques have been investigated so far to increase the rangeability of the compressor without excessively reducing the efficiency. One of the most exploited solutions is represented by the use of upstream axial variable inlet guide vanes (VIGV) to impart a pre-whirl angle to the inlet flow. In the pre-design phase of a new stage or when selecting, for example, an existing unit from an industrial catalogue, it is however not easy to get a prompt estimation of the attended modifications induced by the VIGV on the performance map of the compressor.
2017-09-04
Technical Paper
2017-24-0023
Karim Gharaibeh, Aaron W. Costall
Abstract Internal combustion engines are routinely developed using 1D engine simulation tools. A well-known limitation is the accuracy of the turbocharger compressor and turbine sub-models, which rely on hot gas bench-measured maps to characterize performance. Such discrete map data is inherently too sparse to be used directly in simulation, and so a preprocessing algorithm interpolates and extrapolates the data to generate a wider, more densely populated map. Methods used for compressor map interpolation vary. They may be mathematical or physical in nature, but there is no unified approach, except that they typically operate on input map data in SAE format. For decades it has been common practice for turbocharger suppliers to share performance data with engine OEMs in this form. This paper describes a compressor map interpolation technique based on the nondimensional compressor flow and loading coefficients, instead of SAE-format data.
2017-09-04
Technical Paper
2017-24-0005
Guillaume Goumy, Pascal Chesse, Nicolas Perrot, Rémi Dubouil
Abstract Downsizing has nowadays become the more widespread solution to achieve the quest for reaching the fuel consumption incentive. This size reduction goes with turbocharging in order to keep the engine power constant. To reduce the development costs and to meet the ever tightening regulations, car manufacturers rely more and more on computer simulations. Thus developing accurate and predictable turbocharger models functioning on a wide range of engine life cases became a major requirement in industrial projects. In the current models, compressors and turbines are represented by look-up tables, experimentally measured on a turbocharger test bench, at steady point and high inlet turbine temperature. This method results in limited maps : on the one hand the compressor surge line and on the other hand the flow resistance curve behind the compressor. Mounted on an engine, the turbocharger encounters a wider scale of functioning points.
2017-07-10
Technical Paper
2017-28-1948
John Samuel Kopppula, Thundil Karuppa Raj Rajagopal, Edison Gundabattini
Abstract The present work is concentrated to study the effect of varying inlet pressures on the dynamics of the suction valve obtained from a hermetic reciprocating compressor. The effect of valve functioning on the efficiency of a compressor is highly acceptable. Rather than the delivery valve, the suction valve has a significant impact on the compressor efficiency. The reed valve in a hermetic compressor is a cantilever type arrangement. The valve operates due to the pressure difference between the suction muffler and the cylinder. The numerical analysis which includes Fluid-structure interaction is used in the present study. The flow and structural domain employed in the present study are modelled with Solidworks 15.0. The fluid structure interaction analysis is a combination of ANSYS Fluent and ANSYS structural. These two are coupled with a system coupling in ANSYS Workbench 16.0. The numerical results obtained from the simulation are validated with the experimental data.
2017-03-28
Technical Paper
2017-01-0893
Marek Tatur, Kiran Govindswamy, Dean Tomazic
Abstract Demanding CO2 and fuel economy regulations are continuing to pressure the automotive industry into considering innovative powertrain and vehicle-level solutions. Powertrain engineers continue to minimize engine internal friction and transmission parasitic losses with the aim of reducing overall vehicle fuel consumption. Strip friction methods are used to determine and isolate components in engines and transmissions with the highest contribution to friction losses. However, there is relatively little focus on friction optimization of Front-End-Accessory-Drive (FEAD) components such as alternators and Air Conditioning (AC) compressors. This paper expands on the work performed by other researchers’ specifically targeting in-depth understanding of system design and operating strategy.
2017-03-28
Technical Paper
2017-01-1025
Qinghe Luo, Baigang Sun, Xi Wang
Hydrogen is a promising energy carrier because it is characterized by a fast combustion velocity, a wide range of sources, and clean combustion products. A hydrogen internal combustion engine (H2ICE) with a turbocharger has been used to solve the contradiction of power density and control NOx. However, the selection of a H2ICE compressor with a turbocharger is very different from traditional engines because of gas fuel. Hydrogen as a gas fuel has the same volume as its cylinder and thus increases pressure and reduces the mass flow rate of air in cylinder for a port fuel injection-H2ICE (PFI-H2ICE). In this study, a general method involving a H2ICE with a turbocharger is proposed by considering the effect of hydrogen on cylinders. Using this method, we can calculate the turbocharged pressure ratio and mass flow rate of air based on the target power and general parameters. This method also provides a series of intake temperatures of air before calculation to improve accuracy.
2017-03-28
Journal Article
2017-01-1032
Xavier Llamas, Lars Eriksson
Downsizing and turbocharging with single or multiple stages has been one of the main solutions to decrease fuel consumption and harmful exhaust emissions, while keeping a sufficient power output. An accurate and reliable control-oriented compressor model can be very helpful during the development phase, as well as for engine calibration, control design, diagnostic purposes or observer design. A complete compressor model consisting of mass flow and efficiency models is developed and motivated. The proposed model is not only able to represent accurately the normal region measured in a compressor map but also it is capable to extrapolate to low compressor speeds. Moreover, the efficiency extrapolation is studied by analyzing the known problem with heat transfer from the hot turbine side, which introduces errors in the measurements done in standard gas stands.
2016-09-20
Technical Paper
2016-01-1996
David R. Markham, J. Michael Cutbirth
Abstract Modern military electronics systems are generating increasingly higher heat loads, necessitating larger capacity thermal management systems (TMSs). These high-capacity TMSs must meet the strict size and weight requirements of these advancing platforms. Commercially available compressor technology can generate sufficient cooling for these systems; however, they are too heavy and expansive. Mainstream Engineering Corporation has developed a compact, lightweight, high-speed screw compressor that can provide a large cooling capacity with a small package envelope. The compressor housing material is light-weight with a low coefficient of thermal expansion (CTE), allowing a wide operating temperature range. The compressor, with a nominal cooling capacity from 20 kW to 60 kW, was tested over a range of saturated suction conditions, pressure ratios, rotational speeds, and oil lubrication conditions.
2016-06-15
Technical Paper
2016-01-1818
Raimo Kabral, Lin Du, Mats Abom, Magnus Knutsson
Abstract The concept of IC engine downsizing is a well-adapted industry standard, enabling better fuel conversion efficiency and the reduction of tailpipe emissions. This is achieved by utilizing different type of superchargers. As a consequence, the additional charger noise emission, at the IC engine inlet, can become a problem. In order to address such problem, the authors of this work have recently proposed a novel dissipative silencer for effective and robust noise control of the compressor. Essentially, it realizes an optimal flow channel impedance, referred to as the Cremer impedance. This is achieved by means of a straight flow channel with a locally reacting wall consisting of air cavities covered by an acoustic resistance, e.g., a micro-perforated panel (MPP). In this paper, an improved optimization method of this silencer is presented. The classical Cremer impedance model is modified to account for mean flow dependence of the optimal wave number.
2016-04-05
Technical Paper
2016-01-1037
Lars Eriksson, Vaheed Nezhadali, Conny Andersson
Modelbased systems engineering is becoming an important tool when meeting the challenges of developing the complex future vehicles that fulfill the customers and legislators ever increasing demands for reduced pollutants and fuel consumption. To be able to work systematically and efficiently it is desirable to have a library of components that can be adjusted and adapted to each new situation. Turbocharged engines are complex and the compressor model serves as an in-depth example of how a library can be designed, incorporating the basic physics and allowing fine tuning as more information becomes available. A major part of the paper is the summary and compilation of a set of rules of thumb for compressor map extrapolation. The considerations discussed are extrapolation to surge, extrapolation to restriction region, and extrapolation out to choking.
2016-04-05
Technical Paper
2016-01-1022
Ahsanul Karim, Anthony Morelli, Keith Miazgowicz, Brian Lizotte, Robert Wade
The use of Swirl-Vanes or Inlet Guide Vanes (IGV) in gas engines is well-known and has demonstrated their ability to improve compressor surge margin at low flow rates. But, the use of swirl-vanes is not too common in large diesel engine turbo-chargers where compressor housing inlet has some form of Casing-Treatment (CT). Recently, Ford engineers tested swirl-vanes in a diesel engine turbocharger where the compressor inlet had a ported shroud casing-treatment and the experimental data showed no improvement in surge margin. Computational Fluid Dynamics (CFD) analyses were performed to investigate reasons why the surge margin did not improve after introducing swirl-vanes at the compressor inlet. The CFD results showed strong interactions between swirling flow at the compressor inlet and flow stream coming out of the compressor inlet casing-treatment.
2016-04-05
Journal Article
2016-01-1027
Bertrand Kerres, Vineeth Nair, Andreas Cronhjort, Mihai Mihaescu
Abstract Turbocharger compressors are limited in their operating range at low mass flows by compressor surge, thus restricting internal combustion engine operation at low engine speeds and high mean effective pressures. Since the exact location of the surge line in the compressor map depends on the whole gas exchange system, a safety margin towards surge must be provided. Accurate early surge detection could reduce this margin. During surge, the compressor outlet pressure fluctuates periodically. The Hurst exponent of the compressor outlet pressure is applied in this paper as an indicator to evaluate how close to the surge limit the compressor operates. It is a measure of the time-series memory that approaches zero for anti-persistence of the time series. That is, a Hurst exponent close to zero means a high statistical preference that a high value is followed by a low value, as during surge.
2016-04-05
Technical Paper
2016-01-1014.01
Shyam K. Menon, Himakar Ganti, Chris Hagen
SAE International has been requested by the author to retract the above referenced paper. The retracted paper has been withdrawn and will no longer be available online or in print.
2016-04-05
Technical Paper
2016-01-0554
José Galindo, Andrés Tiseira, Roberto Navarro, Daniel Tarí, Hadi Tartoussi, Stéphane Guilain
Abstract 0D-1D codes allow researchers to obtain a prediction of the behavior of internal combustion engines with little computational effort. One of the submodels of such codes is devoted to the centrifugal compressor. This model is often based on the compressor performance maps, therefore requiring the extrapolation of the maps so that all possible operating conditions are covered. Particularly, a suitable extrapolation of isentropic efficiency map is sought. This work first examines different available methods for compressor efficiency extrapolation into off-design conditions. No method is found to provide satisfactory results at all extrapolated regions: low and high compressor speeds and low compression ratio at measured speeds. Hence, a new method is proposed and its accuracy is assessed with the aid of compressor off-design measurements.
2016-04-05
Technical Paper
2016-01-1311
Tsuyoshi Kanuma, Katsumi Endo, Fumiaki Maruoka, Hiroshi Iijima, Makoto Kawamura, Keisuke Nakazawa, Eiki Yanagawa
Abstract 1 The vane-type rotary compressor of a heating, ventilating, and air conditioning system (HVAC system) is simple and compact but may emit noise due to the collision between the vanes and the cylinder wall. Several studies have been conducted on this chattering noise, with a focus on the noise associated with the compressor revolution speed, temperature, suction pressure, and exhaust pressure. However, such investigations are not sufficient to reveal the behavior of the vane movement in its entirety. To minimize the chattering noise, the details of the mechanism of such vane-operating noise must be investigated by analyzing the behavior of the vanes as a function of time. The vanes move according to the balance between the front and rear pressures. This report describes a novel visualization technique with which to monitor the motion of a vane under given operating conditions. In addition, a method of measuring the pressure affecting the movement of the vanes is discussed.
2016-04-05
Journal Article
2016-01-1184
Kyoung-Ku Ha, Chang Ha Lee, Chi Myung Kim, Sae Hoon Kim, Byung Ki Ahn
Abstract The subject of this study is a centrifugal compressor for Fuel Cell Electric Vehicles (FCEV). Recently there is a growing interest in FCEVs since they are considered a realistic solution to environmental regulations for passenger cars to reduce emissions. Water vapor is the only byproduct of a reaction in the Proton Electrolyte Membrane (PEM) fuel cell stack which generates electricity with oxygen from the surrounding air and hydrogen from a fuel tank. Auxiliary systems called Balance of Plant (BOP) serve to provide air and hydrogen to the stack in a correct ratio. The compressor is one of key components of this system because compression of the intake air brings an increase in efficiency and power density of the FCEV. This paper presents the characteristics of a 10 kW class centrifugal compressor with an oil-free bearing system. It consists of a shaft, two airfoil journal bearings and a pair of thrust bearings.
2016-04-05
Technical Paper
2016-01-0247
Jiu Xu, Predrag Hrnjak
Abstract Automotive air conditioning compressor produces an annular-mist flow consisting of gas-phase refrigerant flow with oil film and oil droplets. This paper reports a method to calculate the oil retention and oil circulation ratio based on oil film thickness, wave speed, oil droplet size, oil droplet speed, and mass flow rate. Oil flow parameters are measured by high-speed camera capture and video processing in a non-invasive way. The estimated oil retention and oil circulation ratio results are compared quantitatively with the measurements from system experiments under different compressor outlet gas superficial velocity. The agreement between video result and sampling measurement shows that this method can be applied in other annular-mist flow analysis. It is also shown that most of the oil exists in film from the mass point of view while oil droplets contributes more to the oil mass flow rate because they travel in a much higher speed.
2016-02-01
Technical Paper
2016-28-0172
Praharsh Srivastava, Kamal Sharma, Raushan Jha
Abstract Rapid advent of mobile air conditioning industry has witnessed a wide use of fixed displacement swash plate compressor due to its small size, compact structure and light weight. An accurate prediction of volumetric efficiency and power of compressor at early stages of design serves as a very useful information for designer. No work regarding the power and volumetric efficiency prediction for double headed fixed displacement swash plate compressor is reported in the existing literature. This paper presents a mathematical model for a double acting fixed displacement swash plate compressor with the objective of evaluating the shaft torque and volumetric efficiency of compressor. Shaft torque, in turn is a measure of compressor power. The geometrical description of swash plate yields a kinematic model to obtain the piston displacement as an explicit function of angle of rotation of shaft.
2015-09-06
Technical Paper
2015-24-2524
José Lujan, José V. Pastor, Héctor Climent, Manuel Rivas
Abstract On actual gasoline turbocharged engines it is common to use a compressor by-pass valve in order to solve the compressor surge problem when the throttle pedal position is released and closes rapidly. The paper deals with a methodology based on experiments to measure the discharge coefficient of an integrated compressor by-pass valve, to understand the possible difference between the steady flow test bench and turbocharger test bench discharge coefficient measurements. To determine if there is some compressor outlet flow field influence due to compressor blades rotation that could modify the discharge coefficient measurement, compared to the steady flow test bench measurements, a fully instrumented turbocharger was used to measure the difference between steady flow test bench and turbocharger test bench discharge coefficients results.
2015-06-15
Technical Paper
2015-01-2132
David L. Rigby, Joseph Veres, Colin Bidwell
Abstract Three-dimensional simulations of the Honeywell ALF502 low pressure compressor (sometimes called a booster) using the NASA Glenn code GlennHT have been carried out. A total of eight operating points were investigated. These operating points are at, or near, points where engine icing has been determined to be likely. The results of this study were used, in a companion paper, for further analysis such as predicting collection efficiency of ice particles and ice growth rates at various locations in the compressor. In an effort to minimize computational effort, inviscid solutions with slip walls are produced. A mixing plane boundary condition is used between each blade row, resulting in convergence to steady state within each blade row. Comparisons of the results are made to other simplified analysis. An additional modification to the simulation process is also presented.
2015-06-15
Technical Paper
2015-01-2139
E.J. Grift, E. Norde, E.T.A. Van der Weide, H.W.M. Hoeijmakers
Abstract In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is provided as input and is a steady flow field solution governed by the Euler equations. The single compressor stage is represented using a cascaded grid. The grid consists of three parts of which the first and the last part are stator parts and the centre part is a rotor. Each particle is modelled as a non-rotating rigid sphere. The remaining model does allow the exchange of heat and mass to and from the particle resulting in a mass, temperature and phase change of the particle. The phase change is based on a perfectly concentric ice core-water film model and it is assumed that the particle is at uniform temperature.
2015-06-15
Journal Article
2015-01-2307
Neil Figurella, Rick Dehner, Ahmet Selamet, Keith Miazgowicz, Ahsanul Karim, Ray Host
Abstract The effect of aerodynamically induced pre-swirl on the acoustic and performance characteristics of an automotive centrifugal compressor is studied experimentally on a steady-flow turbocharger facility. Accompanying flow separation, broadband noise is generated as the flow rate of the compressor is reduced and the incidence angle of the flow relative to the leading edge of the inducer blades increases. By incorporating an air jet upstream of the inducer, a tangential (swirl) component of velocity is added to the incoming flow, which improves the incidence angle particularly at low to mid-flow rates. Experimental data for a configuration with a swirl jet is then compared to a baseline with no swirl. The induced jet is shown to improve the surge line over the baseline configuration at all rotational speeds examined, while restricting the maximum flow rate. At high flow rates, the swirl jet increases the compressor inlet noise levels over a wide frequency range.
2015-04-14
Journal Article
2015-01-1172
Wan Yu, Xu Sichuan, HuaiSheng Ni
Abstract Even though air compressors for traditional vehicles and fuel cell vehicles (FCVs) share many similarities, a fuel cell vehicle cannot directly employ the effective and mass-produced traditional vehicles' air compressors. This is because the fuel cell vehicles have special requirements, such as oil free, low flow rate with high pressure ratio, high efficiency, and low weight and volume. In order to find suitable air compressors to match the fuel cell system (FCS)'s requirements, different air compressors' performance and physical characteristics are compared. These air compressors include screw compressor with expander, roots compressor with expander, turbocompressor, and scroll compressor with expander. The comparison and analysis is both theoretical and practical. Results show that the turbocompressor and the roots compressor/expander have higher performance compared to the others in the aspects of input power, system efficiency, weight, and volume.
2015-04-14
Technical Paper
2015-01-1289
Fabian Herbst, Peter Eilts
Abstract A key technology for further improving the efficiency of gasoline engines lies in downsizing in combination with turbocharging. Decreasing the engine displacement greatly increases the demands on the turbocharging system. The charging of the engine with a single-stage turbocharger leads to a compromise to fulfill the requirements of the nominal power of the engine and the low-end torque. To avoid the use of complex two-stage boosting systems, it is necessary to increase the pressure ratio and the air flow rate at the same time. The wide speed and airflow range of gasoline engines intensify this trade-off. The use of a variable geometry turbine (VGT), additionally equipped with a wastegate bypass, offers great potential to meet the requirements on the turbine side. The range of stable operation of the compressor is limited by choke at high mass flow rates and surge at low mass flow rates.
2015-04-14
Technical Paper
2015-01-1287
Silvia Marelli, Giulio Marmorato, Massimo Capobianco, Andrea Rinaldi
In the last few years, the effect of diabatic test conditions on compressor performance maps has been widely investigated leading some authors to propose different correction models. The accuracy of performance maps constitutes the basis of the turbocharger matching with the engine, for which 1D procedures are more and more adopted. The classical quasi-steady approach generally used is based on the employment of compressor and turbine characteristic maps assuming adiabatic turbocharger conditions. The aim of the paper is to investigate the effect of heat transfer phenomena on the experimental definition of turbocharger maps, focusing on compressor performance. This work was developed within a collaboration between the Polytechnic School of the University of Genoa and CRITT M2A. The compressor steady flow behavior was analyzed through tests performed on different test rigs operating at the University of Genoa and at CRITT M2A, under various heat transfer conditions.
2015-04-14
Technical Paper
2015-01-1280
Ahsanul Karim, Keith Miazgowicz, Brian Lizotte
The stable operation of turbocharger compressor at low flow rates is important to provide low end engine torque for turbocharged automotive engines. Therefore, it is important to be able to predict the lowest flow rates at different turbocharger speeds at which the surge phenomenon occurs. For this purpose, three-dimensional Computational Fluid Dynamics (CFD) simulations were performed on the turbocharger compressor including the entire compressor wheel and volute. The wheel consisted of six main and six splitter blades. Historically, flow bench and engine testing has been used to detect surge phenomenon. However a complete 3D CFD analysis can be performed upfront in the design to calculate low end compressor surge performance. The analyses will help understand the fundamental mechanisms of stalled flow, the surge phenomenon, and impact of compressor inlet conditions on surge.
2015-04-14
Journal Article
2015-01-0662
Weiguo Zhang, Mac Lynch, Robert Reynolds
Abstract A turbocharger is currently widely used to boost performance of an internal combustion engine. Generally, a turbocharger consists of a compressor which typically is driven by an exhaust turbine. The compressor will influence how the low frequency engine pulsation propagates in the intake system. The compressor will also produce broad-band flow induced sound due to the turbulence flow and high frequency narrowband tonal sound which is associated with rotating blade pressures. In this paper, a practical simulation procedure based on a computational fluid dynamics (CFD) approach is developed to predict the flow induced sound of a turbocharger compressor. In the CFD model of turbocharger compressor, the unsteady, moving wheel, detached eddy simulation (DES) approach are utilized. In this manner, both the broad-band and narrow-band flow induced sound are directly resolved in the CFD computation.
2015-04-14
Technical Paper
2015-01-0139
Harish Kumar Gangwar, Ankur Sharma, Dipak Dabhole, Ambekar Prasad
Abstract Today urban buses are equipped with more air consuming devices for an example pneumatic doors, exhaust brake, air suspension and in SCR system to name a few. This has resulted in higher air demand leading to high compressor duty cycles which cause conditions (such as higher compressor head temperatures) that may adversely affect air brake charging system performance. These conditions may require additional maintenance due to a higher amount of oil vapor droplets being passed along into the air brake system. Factors that add to the duty cycle are air suspension, additional air accessories, use of an undersized compressor, frequent stops, excessive air leakage from fittings, connections, lines, chambers or valves, etc. This paper discussed about methodology used to reduce air consumption of air consuming devices used in urban bus application. Performance assessment of air consuming devices with minimum available air pressure was conducted and found satisfactory.
2015-04-14
Technical Paper
2015-01-1715
Farouq Meddahi, Alain Charlet, Yann Chamaillard, Christian Fleck
Abstract Compressor models play a major role as they define the boost pressure in the intake manifold. These models have to be suitable for real-time applications such as control and diagnosis and for that, they need to be both accurate and computationally inexpensive. However, the models available in the literature usually fulfill only one of these two competing requirements. On the one hand, physics-based models are often too complex to be evaluated on line. On the other hand, data-based models generally suffer insufficient extrapolation features. To combine the merits of these two types of models, this work presents an extended approach to compressor modeling with respect to thermo- and aerodynamic losses. In particular, the model developed by Martin et al. [1] is augmented to explicitly incorporate friction, incidence and heat transfer losses. The resulting model surpasses the extrapolation properties of data-based models and facilitates the generation of extended lookup tables.
2015-04-14
Journal Article
2015-01-1720
Vincenzo De Bellis, Fabio Bozza, Silvia Marelli, Massimo Capobianco
Downsizing is widely considered one of the main path to reduce the fuel consumption of spark ignition internal combustion engines. As known, despite the reduced size, the required torque and power targets can be attained thanks to an adequate boost level provided by a turbocharger. However, some drawbacks usually arise when the engine operates at full load and low speeds. In fact, in the above conditions, the boost pressure and the engine performance is limited since the compressor experiences close-to-surge operation. This occurrence is even greater in case of extremely downsized engines with a reduced number of cylinders and a small intake circuit volume, where the compressor works under strongly unsteady flow conditions and its instantaneous operating point most likely overcomes the steady surge margin. In the paper, both experimental and numerical approaches are followed to describe the unsteady behavior of a small in-series turbocharger compressor.
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