| 1. |
- Lejon, Marcus, 1986, et al.
(author)
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Multidisciplinary Design of a Three Stage High Speed Booster
- 2017
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In: ASME Turbo Expo 2017: Turbine Technical Conference and Exposition. - : ASME Press. ; 2B-2017
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Conference paper (peer-reviewed)abstract
- The paper describes a multidisciplinary conceptual design of an axial compressor, targeting a three stage, high speed, high efficiency booster with a design pressure ratio of 2.8. The paper is outlined in a step wise manner starting from basic aircraft and engine thrust requirements, establishing the definition of the high speed booster interface points and its location in the engine. Thereafter, the aerodynamic 1D/2D design is carried out using the commercial throughflow tool SC90C. A number of design aspects are described, and the steps necessary to arrive at the final design are outlined. The SC90C based design is then carried over to a CFD based conceptual design tool AxCent, in which a first profiling is carried out based on a multiple circular arc blade definition. The design obtained at this point is referred to as the VINK compressor. The first stage of the compressor is then optimized using an in-house optimization tool, where the objective functions are evaluated from detailed CFD calculations. The design is improved in terms of efficiency and in terms of meeting the design criteria put on the stage in the earlier design phases. Finally, some aeromechanical design aspects of the first stage are considered. The geometry and inlet boundary conditions of the compressor are shared with the turbomachinery community on a public server. This is intended to be used as a test case for further optimization and analysis.
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| 2. |
- Binder, Christian, 1988-, et al.
(author)
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Phosphor Thermometry for In-Cylinder Surface Temperature Measurements in Diesel Engines
- 2019
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In: Measurement science and technology. - 0957-0233 .- 1361-6501.
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Journal article (other academic/artistic)abstract
- Surface temperature measurements in technically relevant applications can be very hallenging and yet of great importance. Phosphor thermometry is a temperature measurement technique that has previously been employed in technically relevant applications to obtain surface temperature. The technique is based on temperature-dependent changes in a phosphor’s luminescence. To improve the accuracy and precision of temperature measurements with this technique, the present study considers, by way of example, the impact of conditions inside the cylinder of a diesel engine on decay time based phosphor thermometry. After an initial, general assessment of the effect of prevailing measurement conditions, this research investigates errors caused by soot luminosity, extinction, signal trapping and changes of phosphors’ luminescence properties due to exposure to the harsh environment. Furthermore, preferable properties of phosphors which are suitable for in-cylinder temperature measurements are discussed. 16 phosphors are evaluated, including four which – to the authors’ knowledge –have previously not been used in thermometry. Results indicate that errors due to photocathode bleaching, extinction, signal trapping and changes of luminescence properties may cause an erroneous temperature evaluation with temperature errors in the order of serval tens of Kelvin.
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| 3. |
- Saha, Ranjan, 1984-, et al.
(author)
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Aerodynamic Implication of Endwall and Profile Film Cooling in a Transonic Annular Cascade
- 2013
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In: 21st ISABE Conference. - Busan, Korea.
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Conference paper (peer-reviewed)abstract
- An experimental study is performed to observe the aerodynamic implications of endwall and profile film cooling on flow structures and aerodynamic losses. The investigated vane is a geometrically similar transonic nozzle guide vane with engine-representative cooling geometry. Furthermore, a new formulation of the cooling aerodynamic loss equation is presented and compared with the conventional methods. Results from a 5-hole pneumatic probe show that the film coolant significantly alters the secondary flow structure. The effect of different assumptions for the loss calculation is shown to significantly change the measured loss.
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| 4. |
- Saha, Ranjan, 1984-, et al.
(author)
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Suction and Pressure Side Film Cooling Influence on Vane Aero Performance in a Transonic Annular Cascade
- 2013
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In: Proceedings of the ASME Turbo Expo. - 9780791855225
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Conference paper (peer-reviewed)abstract
- An experimental study on a film cooled nozzle guide vane has been conducted in a transonic annular sector to observe the influence of suction and pressure side film cooling on aerodynamic performance. The investigated vane is a typical high pressure gas turbine vane, geometrically similar to a real engine component, operated at an exit reference Mach number of 0.89. The aerodynamic results using a five hole miniature probe are quantified and compared with the baseline case which is uncooled. Results lead to a conclusion that the aerodynamic loss is influenced substantially with the change of the cooling flow rate regardless the positions of the cooling rows. The aerodynamic loss is very sensitive to the blowing ratio and a value of blowing ratio higher than one leads to a considerable higher loss penalty. The suction side film cooling has larger influence on the aerodynamic loss compared to the pressure side film cooling. Pitch-averaged exit flow angles around midspan remain unaffected at moderate blowing ratio. The secondary loss decreases (greater decrease in the tip region compared to the hub region) with inserting cooling air for all cases compared to the uncooled case.
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| 5. |
- Marimon Giovannetti, Laura, et al.
(author)
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Multi-wing sails interaction effects
- 2022
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In: SNAME 24th Chesapeake Sailing Yacht Symposium, CSYS 2022. - : The Society of Naval Architects and Marine Engineers.
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Conference paper (peer-reviewed)abstract
- The effects of multiple wings interacting and the change in efficiency due to those effects as well as optimal sheeting angles are becoming an important area of study with the advent of wind-propelled ships for goods transport. This research presents a first analysis of wind tunnel tests carried out at the University of Southampton R.J. Mitchell wind tunnel where three wings are subject to turbulent flow with Reynolds number in excess of 1 million. A range of possible variations of ship heading and apparent wind angles are tested taking into consideration the blockage effects and the geometrical characteristics of the working section. The forces and moments are captured on each individual wing as well as in the overall wind tunnel balance with 6-components dynamometers. Furthermore, pressure sensors and PIV data are recorded during the tests to provide the experimental campaign with results that can validate both qualitatively and quantitatively the numerical tools developed to aid the design stage of wind propelled vessels.
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| 6. |
- Aghaali, Habib, 1981-, et al.
(author)
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Turbocharged SI-Engine Simulation with Cold and Hot-Measured Turbocharger Performance Maps
- 2012
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In: Proceedings of ASME Turbo Expo 2012, Vol 5. - : ASME Press. - 9780791844717 ; , s. 671-679
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Conference paper (peer-reviewed)abstract
- Heat transfer within the turbocharger is an issue in engine simulation based on zero and one-dimensional gas dynamics. Turbocharged engine simulation is often done without taking into account the heat transfer in the turbocharger. In the simulation, using multipliers is the common way of adjusting turbocharger speed and parameters downstream of the compressor and upstream of the turbine. However, they do not represent the physical reality. The multipliers change the maps and need often to be different for different load points. The aim of this paper is to simulate a turbocharged engine and also consider heat transfer in the turbocharger. To be able to consider heat transfer in the turbine and compressor, heat is transferred from the turbine volute and into the compressor scroll. Additionally, the engine simulation was done by using two different turbocharger performance maps of a turbocharger measured under cold and hot conditions. The turbine inlet temperatures were 100 and 600°C, respectively. The turbocharged engine experiment was performed on a water-oil-cooled turbocharger (closed waste-gate), which was installed on a 2-liter gasoline direct-injected engine with variable valve timing, for different load points of the engine. In the work described in this paper, the difference between cold and hot-measured turbocharger performance maps is discussed and the quantified heat transfers from the turbine and to/from the compressor are interpreted and related to the maps.
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| 7. |
- Sarmast, Sasan, et al.
(author)
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Validation of the actuator line and disc techniques using the New Mexico measurements
- 2016
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In: Journal of Physics, Conference Series. - : Institute of Physics (IOP). - 1742-6588 .- 1742-6596. ; 753:3
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Journal article (peer-reviewed)abstract
- Actuator line and disc techniques are employed to analyse the wake obtained in the New Mexico wind turbine experiment. The New Mexico measurement campaign done in 2014 is a follow-up to the MEXICO campaign, which was completed in 2006. Three flow configurations in axial flow condition are simulated and both computed loads and velocity fields around the rotor are compared with detailed PIV measurements. The comparisons show that the computed loadings are generally in agreement with the measurements under the rotor's design condition. Both actuator approaches under-predicted the loading in the inboard part of blade in stall condition as only 2D airfoil data were used in the simulations. The predicted wake velocities generally agree well with the PIV measurements. In the experiment, PIV measurements are also provided close to the hub and nacelle. To study the effect of hub and nacelle, numerical simulations are performed both in the presence and absence of the hub geometry. This study shows that the large hub used in the experiment has only small effects on overall wake behaviour.
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| 8. |
- Van der Kelen, Christophe, 1986-, et al.
(author)
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Identification of the full anisotropic flow resistivity tensor for multiple glass wool and melamine foam samples
- 2013
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 134:6, s. 4659-4669
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Journal article (peer-reviewed)abstract
- The flow resistivity tensor, which is the inverse of the viscous permeability tensor, is one of the most important material properties for the acoustic performance of porous materials used in acoustic treatments. Due to the manufacturing processes involved, these porous materials are most often geometrically anisotropic on a microscopic scale, and for demanding applications, there is a need for improved characterization methods. This paper discusses recent refinements of a method for the identification of the anisotropic flow resistivity tensor. The inverse estimation is verified for three fictitious materials with different degrees of anisotropy. Measurements are performed on nine glass wool samples and seven melamine foam samples, and the anisotropic flow resistivity tensors obtained are validated by comparison to measurements performed on uni-directional cylindrical samples, extracted from the same, previously measured cubic samples. The variability of flow resistivity in the batch of material from which the glass wool is extracted is discussed. The results for the melamine foam suggest that there is a relation between the direction of highest flow resistivity, and the rise direction of the material.
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| 9. |
- Van der Kelen, Christophe, et al.
(author)
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Inverse estimation of static flow resistivity in porous materials : discussion of the method and results for two tested porous materials
- 2011
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Conference paper (other academic/artistic)abstract
- Porous materials are widely used in applications which focus on noise andvibration control. Their thermal, mechanical and acoustical properties arebenecial for the use of these materials in aeronautical and vehicle industries.Standard measurements for the characterization of porous materials exist andare carried out in many laboratories worldwide. However, these measurementsdo not always consider the possible anisotropy, present in porous materials.The production process of porous materials introduces an inherent geometricanisotropy in the material at micro scale, which in uences the materialproperties at macro scale. It has been shown by Khurana et al. [3] thatthe anisotropy can have a signicant in uence on the acoustical behaviourof the material, especially if the angle of incidence is increased. One ofthe macroscopic parameters, which is important for the performance ofthese material in acoustical applications, is the static ow resistivity. Themethodology to measure the ow resistivity in porous materials is described inISO 9053 [2], giving the ow resistivity of a porous material along one direction.These unidirectional measurements do not allow for a full characterization ofthe ow resistivity tensor, and hence a proper characterization of the porousmaterial. The identication method developed by Goransson et al. [1] providesa non-destructive measurement method to determine the static ow resistivitytensor. The method is based on an inverse estimation of the measured pressure drops over a cubic material sample.The method as described in the work of Goransson et al. [1] has beenimproved in several ways. The Globally Convergent Method of MovingAsymptotes (GCMMA) [5] , which assures convergence, has replaced theMethod of Moving Asymptotes (MMA) [4]. Secondly, the approach of inverseestimation has been veried for a wide range of anisotropy, by setting articialand a priori known anisotropic ow resistivity tensors as a target in theestimation. Furthermore, another approach towards the problem has beentested, in which the focus is on the eigenvalues and eigenvectors of the tensor,in stead of the independent components. In addition, a more precise descriptionof the errors will be presented as well as an error estimation.This method for identication of the anisotropic ow resistivity tensorhas been applied to two dierent porous materials, a brous glass wool anda Melamine foam. The two materials are expected to show dierent degreesof anisotropy with respect to ow resistivity. Glass wool is assumed to betransversely isotropic while the level of anisotropy of Melamine is not asobvious. The full anisotropic ow resistivity tensors of the tested glass wooland Melamine samples are presented, together with their principal valuesand directions. The eigenvalue decomposition provides an insight into theconnection between the directionality of the ow resistivity in each material,and its production process. The overall approach of the method is validated bycomparing the estimated ow resistivity tensors to the ow resistivity measuredin cylindrical samples extracted from the cubic samples tested. Furthermore, astudy of the homogeneity in density and ow resistivity for the two materialsshows that these properties vary within the block of material.References[1] P. Goransson, R. Guastavino, and N. E. Horlin. Measurement and inverseestimation of 3D anisotropic ow resistivity for porous materials.Journalof Sound and Vibration, 327:354{367, 2009.[2] ISO 9053:1991: Acoustics { materials for acoustical applications {determination of air ow resistance, 1991.[3] P. Khurana, L. Boeckx, W. Lauriks, P. Leclaire, O. Dazel, and J.F. Allard.A description of transversely isotropic sound absorbing porous materials bytransfer matrices.Journal of the Acoustical Society of America, 125:915{921,2008.[4] K. Svanberg. The method of moving asymptotes - a new method forstructural optimization.International Journal for Numerical methods inEngineering, 24:359{373, 1987.
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| 10. |
- Van der Kelen, Christophe, 1986-, et al.
(author)
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Measurement and Inverse Estimation of the Full Anisotropic Flow Resistivity Tensor of Glass Wool
- 2010
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Reports (other academic/artistic)abstract
- The air flow resistivity of nine adjacent glass wool samples is measured and estimated using a previously published method. The samples are extracted from a large slab of glass wool material. Identifying the full flow resistivity tensors for nine adjacent cubic glass wool samples allows for an estimation of the spatial distribution of normal and planar flow resistivity throughout the measured material. The average density of the samples tested is 27.8 kg/m3. The estimated flow resistivity tensors are validated by comparison to uni-directional measurements on cylindrical samples, extracted from the cubic glass wool samples tested. Furthermore, the uni-directional measurement method is studied, providing useful insights on the effect of sample thickness on the measured flow resistivity for an anisotropic material.
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