The aim of this master’s thesis is the optimal design of swirl turbines for small water power plant. It is described a different possibilities of turbine‘s install for locality Vrchlabí. It presents a design of turbines and draft tubes. For the installation of turbines is computed theoretical production of annual electric energy. Furthermore it describes a design of supply channel and intake structure.

This diploma thesis deals with hydraulic potential energy of water flows. It also deals with Swirlturbine which is used for water flows with low fall. The optimal design of Swirlturbine at hydraulic structure Chocerady was the main part of this diploma thesis. Part of the diploma thesis is proposal of power plant, solution inlet and inlet swirls, next vent valve and the issue of the draft tube. The thesis includes the proposal of belt gear and strenght analysis of shaft and bearings.

This diploma thesis describes design of blade geometry of swirl turbines with different blade row density for given parameters Q11 = 1,9 [m3s-1], n11 = 170 [min-1], H=2,5 m, and =0,8. Goal is to found out differences between designs with high count of runner blades and design with fewer blades. Comparison of computed characteristics of three, seven and nine bladed runners is given.

The master´s thesis focuses on design of intake manifold with swirl flap for diesel engine. In addition to the design of sub-components of the intake manifold are also investigated the influence of new solutions on engine parameters. The influence of the new solution is compared to the original version and a reference model simulating intake manifold used by competitors. After simulation of thermodynamics and fluid flow are evaluated each variants.

Although pre-swirlers play a determinant role in the transport of air from stationary parts to rotating holes, knowledge about their actual performance is limited. Therefore, this paper aims to relate how the pre-swirler pressure drop affects the performance of different pre-swirlers in terms of discharge coefficient, adiabatic pre-swirl effectiveness, and swirl ratio. The results are extracted from numerical simulations carried out on three different designs, two guide vanes, and a nozzle. When available, the results are compared to experimental data. The guide vanes have shown similar responses to the pressure drop variations. Their discharge coefficients remain relatively insensitive with an average value of 97%. The swirl ratio range from 0.704 to 1.013 and 0.703 to 1.023 respectively for a pressure drop varying from 3 to 7 bars. The adiabatic pre-swirl effectiveness is of 96% and 94%, respectively, under steady state operation.The nozzle design has shown inferior performance as compared to the guide vane designs. Its discharge coefficient remains around 91% and the swirl ratio varies between 0.678 and 1.121 for a pressure drop ranging from 3 to 10 bars. Under steady state operation, the adiabatic pre-swirl effectiveness is 1.22. The influence of through-flows on the aforementioned parameters was also analyzed. It was observed that the through-flow deteriorates the performance of the pre-swirlers, whether in terms of dimensionless pre-swirl effectiveness, or swirl ratio. The discharge coefficient was however not affected.

Three-dimensional turbulent flow in a cylindrical hydrocyclone is considered and studied by means of computational fluid dynamics using software packages CFX and Fluent. The aim has been to identify the methods that can be used for accurate simulation of the flow in three-dimensional configurations in hydrocyclones at high swirl numbers. As a starting point, swirling pipe flows created by tangential inlets, where detailed experimental data were available in literature, were considered. It was found that the velocity profiles for the flow with a swirl number of 2.67 could be predicted accurately using a Reynolds stress model and an accurate numerical discretization on a fine-enough mesh. At a higher swirl number, 7.84, under-prediction in the tangential velocity profiles was observed; however the prediction of the axial velocity profiles was satisfactory. The validated methods were then used to simulate the flow in a cylindrical hydrocyclone at a swirl number as large as 21. The calculated tangential velocity profiles were compared against experimental data measured with a pitometer. Acceptable agreements were recorded except near the geometric axis of the cyclone. Due to the lack of the aircore in the numerical model, disagreements near the axis of the cyclone could be expected to some extent. Numerical experiments performed in the present work indicated that the RNG k-ε model is not likely to be capable to predict highly swirling flows accurately and a Reynolds stress model is required. For three-dimensional models, where the computing capacity and the available memory set strong restrictions on the computational mesh, optimizing the maximum mesh resolution available play an important role on the accuracy and stability of the solution procedure. The most stable results in the present study were found using the Reynolds stress model proposed by Launder et al. on an as regular and structured mesh as possible using a higher order discretization scheme in Fluent. Therefore, the meshing capabilities of the pre-processor, the available turbulence models and the accuracy of the numerical methods must be considered in parallel. Acceptable results were also generated using the Baseline Reynolds stress model implemented in CFX, however, only with a transient procedure which was likely to be more time-consuming. Present simulations present a complex flow structure in the cylindrical cyclone with a double axial flow reversal. The effect of such a flow pattern on the fractionation of the fibres with small differences in density needs to be investigated in future studies. / QC 20101207

The purpose of this thesis has been to evaluate the use of a swirl blade in the uphill teeming process through plant trials. Two series of trials were carried out at Scana Steel Stavanger AS. In the trials a divergent entrance nozzle with a 62° outlet angle were used when casting duplex stainless steel on a base plate with two 6.2 tons ingots. All molds were burned onto the ingots; leading to problems with emptying the ingots from the molds and severe damages on the molds. To get a better insight during the casting and understand why the molds were burned onto the ingots; during the second series of trials one mold on each base plate were filmed in the beginning of the casting process. Evaluation of the castings indicated that splashing on the mold wall at an initial stage was one reason for the mold burned onto the ingot. Further, material samples were collected to evaluate the non-metallic inclusion composition and distribution with SEM when casting with a swirl blade compared to when casting without. The area percentage of the inclusions in the samples was 1% and 2% for samples casted with and without swirl blade respectively with d=2.8 mm. The inclusion size also varied for samples casted with and without swirl blade; 98% of the inclusions were in the size range of 0-10 μm when casted with and in the size range 0-20 μm when casted without swirl blade. / Syftet med denna uppsats har varit att utvärdera användningen av swirlblad i götgjutningsprocessen. Två serier med försök har utförts på Scana Steel Stavanger AS. I försöken användes en inloppssten med 62°-vinklat utlopp, där duplexa rostfria stål göts på stigplan med två 6,2 tons kokiller. Alla kokiller brände fast på göten, vilket ledde till svårigheter vid urtag av göten samt skador på kokillerna. För att få en bättre förståelse av varför kokillerna brände fast, filmades ett göt på vardera stigplan under den andra försöksserien. Utvärdering av försöken indikerar att en anledning till att kokillerna brände fast på göten var att det stänkte upp stål på kokillväggen i ett tidigt stadium. Vidare har materialprover samlats in för att utvärdera sammansättningen samt utspridningen av icke-metalliska inneslutningar i SEM då göt gjutits med swirlblad jämfört med utan. Area procenten i proverna var 1% och 2% då proverna gjutits med respektive utan swirlblad, med d=2.8 mm. Även storleken på inneslutningarna i prover som gjutits med och utan swirlblad skiljde sig åt, 98% av inneslutningarna var i storleksintervallet 0-10 μm för prover gjutna med swirlblad medan de som gjutits utan var i storleksintervallet 0-20 μm. / JK24053

Preliminary designs for the cylinder heads of Scania’s next generation Diesel Engine have been investigated by the means of PIV measurements on a steady test rig. General structures present in the flow have been investigated, with a specific focus on Swirl motion due to its well documented impact on combustion efficiency and pollution generation. The first set of measurements was acquired in the tumble plane. A method to perform efficiently PIV measurements was introduced, which consists in rotating the experimental setup rather than the PIV measurement instruments. As a consequence, a considerable amount of work is saved and a great number of measurement planes can be acquired. This method has allowed to reconstruct a 3D3C picture of the flow in the cylinder. Such 3D3C direct measurement of flow in a test rig cylinder had not been reported previously in the literature, as far as the author is aware of it. The second set of measurements was acquired in the swirl plane. General patterns in the swirl velocity fields have been identified. The author introduces the hypothesis that shifting down the measurement position may, to some extend, be equivalent to observing the flow evolve in time in the real engine situation. Measurement performed far enough under the valves exhibit clear and stable swirling vortex structure with the cylinder heads investigated. This may explain for the validity of the combustion models used in the industry that, despite apparent over simplification of the flow situation, have proved in good agreement with engine tests.

No description available.

An atmospheric pressure swirl-stabilized methane-air burner has been developed as a test platform for nanosecond repetitively pulsed (NRP) discharge plasma-assisted combustion research. Qualitative flame and plasma discharge characterizations were conducted with high-speed video and low-light ICCD imagery, along with a modal acoustic analysis of the entire assembly. A large eddy simulation (LES) of the burner was created using the commercial solver Ansys Fluent to investigate the plasma effects on swirl-stabilized turbulent combustion. A modified version of the solver's premixed combustion mechanism is presented along with a phenomenological plasma discharge model to simulate plasma-assisted combustion. Cold flow particle image velocimetry (PIV) data were collected to validate the non-reacting flow field and assess non-reacting NRP discharge effects. Optical emission spectroscopy (OES) measurements of the second positive system (SPS) of nitrogen mapped temperature characteristics of NRP discharge bursts for comparison to time-resolved simulation data. Finally, time-averaged CH* chemiluminescence data were collected to qualitatively assess the effects of plasma on the experimental burner and simulated flame structure. Overall, the phenomenologically-based combustion mechanism proposed in this work shows good agreement with several experimental observations and provides a promising framework for future plasma-assisted combustion modeling.