Search for dissertations about: "thermal discharge model"

Showing result 1 - 5 of 20 swedish dissertations containing the words thermal discharge model.

2. 1. The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head

   Author : Chi Thanh Tran; Tomas Lefvert; Harri Tuomisto; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; light water reactor; hypothetical severe accident; accident progression; accident scenario; core melt pool; heat transfer; turbulent natural convection; heat transfer coefficient; phase change; mushy zone; crust; lower plenum; analytical model; effective convectivity model; CFD simulation; Thermal energy engineering; Termisk energiteknik;

   Abstract : Severe accidents in a Light Water Reactor (LWR) have been a subject of intense research for the last three decades. The research in this area aims to reach understanding of the inherent physical phenomena and reduce the uncertainties in their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors, and to evaluation of the proposed accident management schemes for mitigating the consequences of severe accidents. READ MORE

4. 2. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

   Author : Tuan Anh Hoang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

   Abstract : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. READ MORE

5. 3. Mechanisms of Electrical Ageing of Oilimpregnated Paper due to Partial Discharges

   Author : Mohamad Ghaffarian Niasar; Hans Edin; Ernst Gockenback; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; oil-impregnated paper; oil; transformer insulation; dielectric frequency response; breakdown strength; ion mobility; thermal ageing; electrical ageing; moisture in paper; life time; thermal breakdown.; Electrical Engineering; Elektro- och systemteknik;

   Abstract : In this thesis, partial discharge (PD) phenomenon in oil-impregnated paper (OIP) is investigated under accelerated electrical stress. The thesis is mainly focused on the characteristic of PD activity and the influence it has on the insulation properties of OIP. READ MORE

6. 4. Computational framework for studying charge transport in high-voltage gas-insulated systems

   Author : Shailendra Singh; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; barrier discharge; low temperature plasma; drift diffusion equation; gaseous dielectrics; gas discharge; streamer propagation; high voltage;

   Abstract : Electrical switchgear industry dealing with transmission and distribution of power is strongly affected by the changing dynamics of climate control. Their main contribution to the global warming is through SF6 gas, having a GWP of 23500 (times of CO2). SF6 plays an important role in providing electrical insulation for these high voltage systems. READ MORE

7. 5. Energy based surgical instruments : With particular focus on collateral thermal injury

   Author : Johan Carlander; Kenth Johansson; Leif Bergkvist; Oliver Gimm; Martin Almquist; Linköpings universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES;

   Abstract : Iatrogenic post-operative nerve dysfunction is a significant problem in many areas of surgery and can be caused by collateral thermal injury from activation of energy based surgical devices (EBD).The aims of this thesis were to: create an animal model in order to compare mono- and bipolar electrosurgery (ES) and an ultrasonic dissection (UD) with regard to collateral thermal nerve injury, and with data of a national multicenter register to study the use of EBD and their potential effects on operation time and complication rates in thyroid surgery. READ MORE