Search for dissertations about: "kavitation"

Showing result 1 - 5 of 10 swedish dissertations containing the word kavitation.

2. 1. Polyethylene – metal oxide particle nanocomposites for future HVDC cable insulation : From interface tailoring to designed performance

   Author : Dongming Liu; Ulf Gedde; Mikael Hedenqvist; Richard Olsson; Linda Schadler; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HVDC; electrical insulation; core-shell nanoparticles; surface modification; silane chemistry; nanocomposites; polyethylene; adsorption; long-term stability; interface; particle dispersion; cavitation; conductivity; HVDC; elektrisk isolation; ytmodifiering; silankemi; nanokompositer; polyeten; adsorption; långtidsstabilitet; ytskikt; partikeldispergering; kavitation; ledningsförmåga; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Abstract : Low-density polyethylene (LDPE) nanocomposites containing metal oxide nanoparticles are considered as promising candidates for insulating materials in future high-voltage direct-current (HVDC) cables. The significant improvement in dielectric properties compared with unfilled polymer is attributed to the large and active interface between the nanoparticles and the polymer. READ MORE

4. 2. CFD MODELLING AND EXPERIMENTS ON AERATOR FLOW IN CHUTE SPILLWAYS

   Author : Penghua Teng; James Yang; Anders Wörman; Anton Schleiss; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spillway Aerator; Cavitation; Air Entrainment; Two-phase Flow; VOF; Mixture Model; Two-Fluid Model; Air Cavity; Cavity Air Pressure; Air Concentration; Shadowgraphic Image Method SIM ; High-speed Particle Image Velocimetry HSPIV ; Bubble Tracking Method BTM ; luftningsramp; kavitation; luftinträngning; tvåfasflöde; VOF; Mixture Model; Two-Fluid Model; luftkavitet; kavitetslufttryck; luftkoncentration; skuggrafisk bildmetod; hastighetsmätning med höghastighetspartikelfotografering; bubbelspårningsmetod; Byggvetenskap; Civil and Architectural Engineering;

   Abstract : A chute spillway is a typical component of large dams for discharging floods. Because of the high water head, the flow velocity in the chute is often in excess of 20 m/s. Consequently, the structure is usually prone to cavitation damages. Flow aeration is evidenced to efficiently eliminate or to mitigate the damages. READ MORE

5. 3. Simulations of cavitation - from the large vapour structures to the small bubble dynamics

   Author : Aurélia Vallier; Strömningsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : Very few people around us know the meaning of the word cavitation, except from those who saw the movie "The Hunt for Red October" and can relate cavitation to Sean Connery in a submarine. Some of them know that it corresponds to the formation of bubbles, due to a pressure drop, and causes erosion and noise. However, cavitation is much more complex. READ MORE

6. 4. Numerical modeling of deforming bubble transport related to cavitating hydraulic turbines

   Author : Daniel Lörstad; Institutionen för energivetenskaper; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gases; fluid dynamics; plasmas; Gaser; fluiddynamik; plasma; Energy research; Energiforskning; Direction Averaged Curvature DAC ; Direction Averaged Normal DAN ; Volume of Solid VOS ; Volume of Fluid VOF ; Lagrangian Particle Tracking LPT ; Large Eddy Simulation LES ; bubble; multiphase; turbulent flows; CFD; hydro-turbine;

   Abstract : Cavitation is a problem in many hydroelectric power plants since it can cause adverse effects on performance and damage to nearby solid surfaces. The concerns of this thesis are the numerical aspects of flow simulations in cavitating hydraulic turbines which contain several difficulties: turbulent and complex flows, steady and moving parts of the geometry, bubble transport and cavitation development. READ MORE

7. 5. CFD and data-driven modeling for safe spillway discharge

   Author : Shicheng Li; Anders Ansell; James Yang; Robert Boes; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Discharge safety; hydraulic design; spillway; discharge capacity; aerator; two-phase flow; air entrainment; energy dissipation; CFD; data-driven modeling; Betongbyggnad; Concrete Structures;

   Abstract : A spillway is a crucial dam structure that regulates water levels and prevents the dam from overtopping. The majority of the dams in the world were constructed before the 1980s. Compared to the current design flood standards, many spillways are undersized, e.g. READ MORE