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  • 1.
    Burström, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Liepaja University.
    Ljung, Anna-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Marjavaara, Daniel
    LKAB Research and Development.
    Grate aerodynamic: Model strategies for gas flow through a 2D iron ore pellet bed2014Conference paper (Refereed)
  • 2. Ebermark, Sofia
    et al.
    Marjavaara, Daniel
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Pressning av SMC: numeriska tryckfältsberäkningar med hjälp av inversmodellering2007In: Svenska Mekanikdagar 2007: Program och abstracts / [ed] Niklas Davidsson; Elianne Wassvik, Luleå: Luleå tekniska universitet, 2007, p. 74-Conference paper (Other academic)
  • 3.
    Hellström, Gunnar
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Marjavaara, Daniel
    Lundström, Staffan
    Parallel CFD simulations of an original and redesigned hydraulic turbine draft tube2007In: Advances in Engineering Software, ISSN 0965-9978, E-ISSN 1873-5339, Vol. 38, no 5, p. 338-344Article in journal (Refereed)
    Abstract [en]

    The design of hydraulic turbine draft tubes has traditionally been based on simplified analytic methods, model and full-scale experiments. In the recent years the use of numerical methods such as computational fluid dynamics (CFD) has increased in the design process, due to the rapid escalation in computer performance. Today with parallel computer architectures, new aspects of flow can be considered. However, several problems have still to be solved before CFD can routinely be applied in product development. This paper aims to investigate the parallel performance of commercial CFD software on homogeneous computer networks, as common solutions encountered in the industry today. In addition, the efficiency improvements obtained in earlier experiments by modifying the shape of the draft tube will be considered, to deduce if the improvements can be captured with aid of CFD. Results from both the steady and the unsteady CFD simulations show that almost full scalability is obtained with the commercial CFD software CFX-5.7.1. Furthermore, no noticeable improvement in the pressure recovery factor or the flow field is noticed in the CFD simulations as compared to experiments. The discrepancy may be to the applied inlet boundary conditions and/or the turbulence model.

  • 4.
    Karlberg, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Marjavaara, Daniel
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Simulation driven processing function development, offering and operation2012In: Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition IMECE2012: November 9-15, 2012, Houston, Texas, USA, New York: American Society of Mechanical Engineers , 2012, Vol. 3, p. 1561-1572Conference paper (Refereed)
    Abstract [en]

    In today’s industry, functional provision is becoming more and more important, necessitating increased simulation support. In this paper, the objective is to present a modeling and simulation approach for simulation-driven design (SDD) to support function development. The scope of this paper is simulation support for developing hardware equipment used in processing industry. The research is founded on industrial needs identified through two parallel interview-based studies in the Swedish process industry. Both companies explore doing business with functional products rather than hardware, in scenarios where the responsibility for and availability of the functions may remain with the service provider. One as-is and one future (to-be) scenario are presented. A decomposition of a general processing function (applicable to both companies) describes how the companies transfer machine input to output specifications. The decomposition includes customer and provider value and the paper demonstrates, as part of the results and based on the SDD approach, how that value may be increased through evaluation and prioritization. Additionally, the SDD approach shows that it is possible to identify a set of solutions which meet the specified requirements, supporting evaluation and prioritization of business offers and activities.

  • 5.
    Lindgren, M.
    et al.
    Luleå tekniska universitet.
    Marjavaara, Daniel
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Automatic design of hydropower flows: the draft tube2002In: Computational technologies for fluid/thermal/structural/chemical systems with industrial applications: presented at the [International Symposium on Computational Technologies for Fluid/Thermal/Chemical/Stress Systems with Industrial Applications], 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9, 2002 / [ed] C.R. Kleijn, New York: American Society of Mechanical Engineers, Pressure Vessels and Piping Division , 2002, Vol. 448, No. 1, p. 299-307Conference paper (Refereed)
    Abstract [en]

    The focus is set on a redesign of an existing draft tube by usage of an automated optimisation based on CFD calculations. By this method a design can be predicted in terms of a predefined objective function, here the pressure recovery factor. The design parameters used are based on spline-functions that are set under certain restrictions. One is that the new design should fit into the old one. The optimisation is performed with the Response Surface Method (RSM) implemented on the commercial code iSIGHT6.0. The flow simulations are carried out with the commercial code, CFX4, with the standard k-ε turbulence model and with boundary conditions based on detailed experimental data. With this set-up and the chosen parameterisation the highest value is found at the edge of the design space allowing for further improvements.

  • 6.
    Ljung, Anna-Lena
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Marjavaara, Daniel
    Discrete and continuous modelling of heat and mass transport in drying of a bed of iron ore pellets2012In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 30, no 7, p. 760-773Article in journal (Refereed)
    Abstract [en]

    Drying of a porous bed of iron ore pellets is here considered by modeling a discrete two-dimensional system of round pellets. As a complement to the two-dimensional model, a continuous one-dimensional model enabling fast calculations is developed. Results from the discrete model show that the temperature front advances faster in areas with large distances between the pellets. In areas with low flow speed, the temperature of the pellets increases with a relatively slow rate. The water inside these pellets will therefore remain for a long time. The continuous model fits the discrete model very well for a regular distribution of equal-sized particles. A discrete model with irregular packing will, compared to the continuous model, show a larger variation in the distribution of temperature and moisture content in the final phase of drying.

  • 7.
    Marjavaara, Daniel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    CFD driven optimering av vattenvägarna i ett vattenkraftverk med hjälp av surrogatmodeller2007In: Svenska Mekanikdagar 2007: Program och abstracts / [ed] Niklas Davidsson; Elianne Wassvik, Luleå: Luleå tekniska universitet, 2007, p. 55-Conference paper (Other academic)
  • 8.
    Marjavaara, Daniel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    CFD driven optimization of hydraulic turbine draft tubes using surrogate models2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The efficiency of a hydraulic reaction turbine is significantly affected by the performance of its draft tube. The shape and velocity distribution at the inlet are, in next turn, two main factors that affects the performance of the draft tube. Traditionally, the design of this component has been based on simplified analytic methods, experimental rules of thumb and model tests. In the last decade or two, the usage of computational fluid dynamics (CFD) has dramatically increased in the design process and will continue to grow due to is flexibility and cost-effectiveness. A CFD-based design search can further be aided with a robust and userfriendly optimization framework. Numerical prediction of the draft tube flow are, on the other hand, challenging and time consuming, caused by its complex flow features, e.g. unsteadiness, turbulence, separation, streamline curvature, secondary flow, swirl, and vortex breakdown. Hence, there is a great need of developing both accurate and reliable CFD models, together with efficient and effective optimization frameworks. In this work, a surrogate-based optimization (SBO) framework has been employed, in order to develop and implement a computer tractable approach to optimize the shape of hydraulic turbine draft tubes. By this methodology, one can replace the expensive CFD model with a surrogate model in the optimizations phase, in order to provide a faster and more effective exploration of the design and solution space. In addition, one gets a better insight into the true relationship between design variables and objective functions. Furthermore, this study has surveyed to enhance the quality and trust of non-trivial draft tube flow simulations. Mainly, since the initial CFD predictions were found to be in poor agreement with model tests, whereby the work has been split into two major parts, one concerning the SBO analysis and the other concerning the validity of the obtained CFD calculations. The outcome of this research, demonstrates the potential and benefits of using surrogate models in the design phase of hydraulic turbines draft tubes. For example, is the computational burden with a SBO framework drastically reduced, compared to solely utilizing a standard optimization framework. It is also preferable to test multiple surrogate models, since the prediction capabilities of it is highly problem dependent and the time cost of doing it is relatively low. The optimization results show moreover similar trends as model tests, illustrating the reliability of the approach. Some quantitative discrepancies are, however, found and it is recommended to further enhance the CFD simulations, by for instance include the runner geometry and/or use more advanced turbulence models in the calculations.

  • 9. Marjavaara, Daniel
    Formoptimering av vattenvägarna i ett vattenkraftverk2005In: Svenska Mekanikdagar 2005, Lund: Lund Institute of Technology , 2005, p. 63-Conference paper (Other academic)
  • 10. Marjavaara, Daniel
    Formoptimering av vattenvägarna i ett vattenkraftverk2003In: SMD 03 : Svenska mekanikdagar : Göteborg 13-15 augusti 2003, Göteborg: Chalmers tekniska högskola , 2003, p. 114-Conference paper (Other academic)
  • 11. Marjavaara, Daniel
    Parameterisation and flow design optimisation of hydraulic turbine draft tubes2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the present energy market, the demands of rehabilitation and modernisation of old constructions are increasing. Among the renewable energy resources, hydropower offers one of the highest potential for further improvements due to the fact that a great number of hydropower plants are ageing and that they are run at off-design conditions. An important part of a low and medium headed hydropower plant is the hydraulic draft tube, where a large portion of the hydraulic losses occurs. The purpose of the draft tube, often being a curved diffuser connecting the runner to the outlet, is to recover kinetic energy and thus creating an artificial head. Traditionally the design has been based on model tests and simplified analytic methods. Today and in the future Computational Fluid Dynamics (CFD) in combination with computer optimisation will be used as a design tool. The numerical prediction of the flow field in the draft tube is however challenging, caused by its complex flow features e.g. unsteadiness, swirl, separation etc. Additional difficulties with the numerical optimisation make the calculations even more demanding, thus several problems have to be solved before it can routinely be applied in product development. The present work investigates the possibilities of using the global Response Surface Methodology technique in combination with CFD in the design process of a hydraulic draft tube. The thesis consists of three papers. In the first paper (Paper A) two different geometric parameterisations of Hölleforsens draft tube geometry, Adapted respectively Profile Design, is studied on one design variable. The result shows on small variation in the pressure recovery and some discrepancies in the dissolution of the draft tube geometry, depending on the evaluated parameterisation. In the second paper (Paper B) the calculation on the Adapted Design parameterisation performed in Paper A is refined, in order to examine how the optimal design is affected by grid size and grid error. A validation of the optimum design is also performed. The outcome reveals that variations in the pressure recovery and the loss factor are still small compared to the experiments, which may be due to the applied inlet conditions. In the third and final paper (Paper C) a three design variable case of Yngeredsforsens draft tube geometry is scrutinized regarding multi objectives and noise analys based on the Iterative Re- weighted Least Square method (IRLS). The result is a draft tube geometry angled to the right, following the swirling properties at the inlet. This optimum right angle configuration is more pronounced with the IRLS method than without.

  • 12. Marjavaara, Daniel
    et al.
    Ebermark, Sofia
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Compression moulding simulations of SMC using a multi-objective surrogate-based inverse modeling approach2009In: Mechanics of composite materials, ISSN 0191-5665, E-ISSN 1573-8922, Vol. 45, no 5, p. 503-515Article in journal (Refereed)
    Abstract [en]

    A multiobjective surrogate-based inverse modeling technique to predict the spatial and temporal pressure distribution numerically during the fabrication of sheet moulding compounds (SMCs) is introduced. Specifically, an isotropic temperature-dependent Newtonian viscosity model of a SMC charge is fitted to experimental measurements via numerical simulations in order to mimic the temporal pressure distribution at two spatial locations simultaneously. The simulations are performed by using the commercial computational fluid dynamics (CFD) code ANSYS CFX-10.0, and the multiobjective surrogate-based fitting procedure proposed is carried out with a hybrid formulation of the NSGA-IIa evolutionary algorithm and the response surface methodology in Matlab. The outcome of the analysis shows the ability of the optimization framework to efficiently reduce the total computational load of the problem. Furthermore, the viscosity model assumed seems to be able to re solve the temporal pressure distribution and the advancing flow front accurately, which can not be said of the spatial pressure distribution. Hence, it is recommended to improve the CFD model proposed in order to better capture the true behaviour of the mould flow.

  • 13. Marjavaara, Daniel
    et al.
    Ebermark, Sofia
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Simulation of Compression moulding of SMC by using a multi-objective surrogate-based inverse modelling approach2008In: Proceedings of the XV International Conference on Mechanics of Composites Material, MCM-2008, 2008Conference paper (Other academic)
  • 14. Marjavaara, Daniel
    et al.
    Kamakoti, R.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Thakur, S.
    Wright, J.
    Shyy, W.
    Steady and unsteady CFD simulations of the Turbine-99 Draft Tube using CFX-5 and STREAM2005In: Turbine-99 III: Proceedings of the third IAHR/ERCOFTAC workshop on draft tube flow, Luleå: Luleå tekniska universitet, 2005, p. 83-99Conference paper (Refereed)
    Abstract [en]

    The numerical prediction of the flow field in a hydraulic turbine draft tube is very challenging due to its complex flow properties and has already been studied in detail in two former ERCOFTAC Turbine-99 workshops. In this third workshop yet another step to determine the state of the art techniques in draft tube flow simulation are taken. Three cases were suggested in the workshop, wherein we have contributed to the first two cases (Case 1 respectively Case 2) in this paper using the CFD codes CFX-5 and Loci-STREAM. For the first case (steady calculation), the turbulence is modeled with the standard k-ε model and Menter's BSL and SST k-ω models, whereas for the second case (unsteady calculation), we use the SST based DES turbulence model. Results from these simulations show that both codes predict about the same main flow structures although significant differences in detailed flow fields are noticed between the two codes and between applied turbulence models.

  • 15. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Automatic shape optimisation of a hydropower draft tube2003In: Proceedings of 4th ASME-JSME Joint Fluids Engineering Conference, American Society of Mechanical Engineers , 2003, Vol. Vol. 2, p. 1819-1824Conference paper (Refereed)
    Abstract [en]

    Draft tube designs have to a large extend been based on intuition and on the experience of the design engineer. In a close future, CFD simulations coupled with optimisation algorithms will assist in the search for an optimal technical solution. Such a shape optimisation technique to redesign an existing draft tube is presented in this paper. By this method, a design can be predicted in terms of a predefined objective function, here the pressure recovery factor. The optimisation is performed with the Response Surface Method (RSM) implemented on the commercial code iSIGHT7.0, while the CFD simulations are carried out with the commercial code CFX4.4. The boundary conditions are based on detailed experimental data and the turbulence is modelled with the standard k-ε turbulence model. With this set-up and with two different parameterisations, Adapted and Profile Design respectively, an optimal geometry of the ERCOFTAC Turbine-99 draft tube can be predicted.

  • 16. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Redesign of a sharp heel draft tube by a validated CFD-optimization2006In: International Journal for Numerical Methods in Fluids, ISSN 0271-2091, E-ISSN 1097-0363, Vol. 50, no 8, p. 911-924Article in journal (Refereed)
    Abstract [en]

    Numerical optimization techniques in flow design are often used to find optimal shape solutions, regarding, for instance, performance, flow behaviour, construction considerations and economical aspects. The present paper investigates the possibilities of using these techniques in the design process of a hydropower plant. This is realized by optimizing the shape of an existing sharp heel draft tube and validating the result with previously performed experiments. The actual shape optimization is carried out with the response surface methodology, by maximizing the average pressure recovery factor and minimizing the energy loss factor. The result from the optimization shows that it is possible to find an optimal solution on rather coarse grids. The location of the optimum is similar to the experiments, but the improvements are unexpectedly small. This surprising result indicates that the simulated flow field does not completely act as the real flow, which may be a result of the applied inlet boundary conditions, insufficient turbulence models and/or the steady flow assumption.

  • 17. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Response surface-based shape optimization of a Francis draft tube2007In: International journal of numerical methods for heat & fluid flow, ISSN 0961-5539, E-ISSN 1758-6585, Vol. 17, no 1, p. 34-45Article in journal (Refereed)
    Abstract [en]

    Purpose - This paper aims to develop an efficient and accurate numerical method that can be used in the design process of the waterways in a hydropower plant. Design/methodology/approach - A range of recently published (2002-2006) works, which aim to form the basis of a shape optimization tool for flow design and to increase the knowledge within the field of computational fluid dynamics (CFD) and surrogate-based optimization techniques. Findings - Provides information about how crude the optimization method can be regarding, for example, the design variables, the numerical noise and the multi objectives, etc. Research limitations/implications - It does not give a detailed interpretation of the flow behaviour due to the lack of validation data. Practical implications - A very useful flow design methodology that can be used in both academy and industry. Originality/value - Shape optimization of hydraulic turbine draft tubes with aid of CFD and numerical optimization techniques has not been performed until recently due to the high CPU requirements on CFD simulations. The paper investigates the possibilities of using the global optimization algorithm response surface methodology in the design process of a full scale hydraulic turbine draft tube.

  • 18. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Shape optimisation of a hydropower draft tube2004In: 22nd IAHR Symposium on Hydraulic Machinery and Systems: Stockholm, Sweden, June 29 - July 2, 2004, Stockholm: IAHR , 2004, Vol. A, p. A03.2.1-A03.2.11Conference paper (Refereed)
  • 19. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Simulation driven design applied to draft tubes using surrogate models2006In: 23rd IAHR Symposium on Hydraulic Machinery and Systems: Yokohama, Japan, October 17 - 21, 2006 ; [conference proceedings], 2006Conference paper (Refereed)
  • 20. Marjavaara, Daniel
    et al.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Goel, Tushar
    Department of Mechanical and Aerospace Engineering, University of Florida.
    Mack, Yolanda
    Department of Mechanical and Aerospace Engineering, University of Florida.
    Shyy, Wei
    Department of Aerospace Engineering, University of Michigan.
    Hydraulic turbine diffuser shape optimization by multiple surrogate model approximations of pareto fronts2007In: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 129, no 9, p. 1228-1240Article in journal (Refereed)
    Abstract [en]

    A multiple surrogate-based optimization strategy in conjunction with an evolutionary algorithm has been employed to optimize the shape of a simplified hydraulic turbine diffuser utilizing three-dimensional Reynolds-averaged Navier-Stokes computational fluid dynamics solutions. Specifically, the diffuser performance is optimized by changing five geometric design variables to maximize the average pressure recovery factor for two inlet boundary conditions with different swirl, corresponding to different operating modes of the hydraulic turbine. Polynomial response surfaces and radial basis neural networks are used as surrogates, while a hybrid formulation of the NSGA-IIa evolutionary algorithm and a ε-constraint strategy is applied to construct the Pareto front from the two surrogates. The proposed optimization framework drastically reduces the computational load of the problem, compared to solely utilizing an evolutionary algorithm. For the present problem, the radial basis neural networks are more accurate near the Pareto front while the response surface performs better in regions away from it. By using a local resampling updating scheme the fidelity of both surrogates is improved, especially near the Pareto front. The optimal design yields larger wall angles, nonaxisymmetrical shapes, and delay in wall separation, resulting in 14.4% and 8.9% improvement, respectively, for the two inlet boundary conditions.

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