Search for dissertations about: "unsteady CFD"

Showing result 11 - 15 of 60 swedish dissertations containing the words unsteady CFD.

2. 11. Experimental Investigation of Three-Dimensional Mechanisms in Low-Pressure Turbine Flutter

   Author : Damian Vogt; Torsten Fransson; Robert Kielb; KTH; []
   Keywords : Life sciences and physical sciences; turbomachinery; flutter; aeroelastic instability; aeroelastic testing; CFD; linearized unsteady numerical method; 3D aerodynamic effects; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP;

   Abstract : The continuous trend in gas turbine design towards lighter, more powerful and more reliable engines on one side and use of alternative fuels on the other side renders flutter problems as one of the paramount challenges in engine design. Flutter denotes a self-excited and self-sustained aeroelastic instability phenomenon that can lead to material fatigue and eventually damage of structure in a short period of time unless properly damped. READ MORE

4. 12. Flutter in sectored turbine vanes

   Author : Olga V. Chernysheva; KTH; []
   Keywords : turbomachinery; aerodynamics; unsteady CFD; design; flutter;

   Abstract : In order to eliminate or reduce vibration problems inturbomachines without a high increase in the complexity of thevibratory behavior, the adjacent airfoils around the wheel areoften mechanically connected together with lacing wires, tip orpart-span shrouds in a number of identical sectors. Although anaerodynamic stabilizing effect of tying airfoils together ingroups on the whole cascade is indicated by numerical andexperimental studies, for some operating conditions suchsectored vane cascade can still remain unstable. READ MORE

5. 13. Low head pumped hydro storage with contra-rotating pump-turbines

   Author : Jonathan Fahlbeck; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy storage; Pumped hydro storage; CFD; Transients; Pump-turbine; Low head; OpenFOAM; Contra-rotating; Hydropower;

   Abstract : The increasing share of electrical energy production by intermittent sources pushes the demand for energy storage. Pumped hydro storage (PHS) has a long history of providing a cost-efficient energy storage solution. However, for PHS to be a viable option, a large head is typically required. READ MORE

6. 14. Numerical Investigation of Some Heat Transfer Topics with Relevance to Gas Turbines

   Author : Arash Saidi; Värmeöverföring; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vakuumteknik; Maskinteknik; vacuum technology; vibration and acoustic engineering; hydraulics; Mechanical engineering; plasma; fluiddynamik; Gaser; Ribbed ducts; intercoolers; EASM; EVM; gas turbine; CFD; heat exchangers; extended surfaces; offset strip fin; heat transfer enhancement; Thermal engineering; applied thermodynamics; Termisk teknik; hydraulik; termodynamik; Gases; plasmas; fluid dynamics; vibrationer; akustik;

   Abstract : The first part of the investigation is related to the heat transfer and fluid flow problem inside ribbed ducts with a square cross section. The typical applications of this problem are in the cooling of gas turbine blades and guiding vanes. The second part is related to application of intercoolers in gas turbine systems. READ MORE

7. 15. Vehicle wakes in side wind

   Author : Magnus Urquhart; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surrogate model; optimization; CFD; wind; crossflow; drag; yaw; cavity; wake; tomographic PIV; aerodynamics;

   Abstract : There is a global push to reduce the energy consumption of passenger vehicles with increasingly stringent targets and regulations. More than one-tenth of Europe's greenhouse gasses are due to passenger vehicles. The aerodynamic drag is a major contributor to energy consumption responsible for more than a quarter of the vehicle's energy usage. READ MORE