Sökning: "Mechanical ventilation"

Visar resultat 1 - 5 av 208 avhandlingar innehållade orden Mechanical ventilation.

  1. 1. A Ventilation Strategy Based on Confluent Jets : An Experimental and Numerical Study

    Författare :Setareh Janbakhsh; Bahram Moshfegh; Alexander Zhivov; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple interacting jets; round jets; confluent jets; wall jet; ventilation strategy; air distribution system; air supply device; ventilation performance; thermal comfort; energy-saving potential; measurement; numerical predictions; RANS turbulence models; renormalization group RNG k– ε ; realizable Re k– ε ; and shear stress transport SST k– ω ;

    Sammanfattning : This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. LÄS MER

  3. 2. Benefits of Spontaneous Breathing : Compared with Mechanical Ventilation

    Författare :László Vimláti; Michael Lichtwarck-Aschoff; Anders Larsson; Lars Wiklund; Carl-Johan Wickerts; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; spontaneous breathing; mechanical ventilation; pulmonary shunt; oxygenation; hypoxic pulmonary vasoconstriction; Anestesiologi och intensivvård; Anaesthesiology and Intensive Care;

    Sammanfattning : When spontaneous breathing (SB) is allowed during mechanical ventilation (MV), atelectatic lung areas are recruited and oxygenation improves thereby. Whether unsupported SB at its natural pattern (without PEEP and at low pressure/small tidal volume) equally recruits and improves oxygenation, and if so by which mechanism, has not been studied. LÄS MER

  4. 3. Ventilation Flow Field Characteristics of a Hydro-Generator Model- An experimental and Numerical Study

    Författare :Hamed Jamshidi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Naphthalene Sublimation Technique; Hydro Power Generator; Ventilation; Experiment; CFD;

    Sammanfattning : Hydro-generators are complex machines used to convert the mechanical energy of the water turbine into electrical energy. Electromagnetic and mechanical losses accompany this energy conversion process which will cause heat generation and temperature increase. Cooling systems are needed to remove this excess heat from hydro-generators. LÄS MER

  5. 4. Modelling of Turbulent Flow and Heat Transfer for Building Ventilation

    Författare :Peng Shia-Hui; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; large eddy simulation; turbulent buoyant convection; ventilation performance assessment; purging flow rate; SGS modelling; ventilation flow; stochastic Markov chain model; turbulence modelling; LRN k-w model; two-equation models; building ventilation; transfer probability; transition regime; modified SGS buoyancy model; energy backscatter;

    Sammanfattning : This thesis contributes to studies on the assessment of building ventilation performance and the development of turbulence models accounting for Low-Reynolds-number (LRN) effects and buoyant convection with heat transfer. Assessments of building ventilation performance are discussed with respect to indoor air distribution and passive contaminant dispersion. LÄS MER

  7. 5. Optimizing mechanical ventilation in extremely preterm infants

    Författare :Linda Wallström; Richard Sindelar; Anders Jonzon; Raffaele Dellaca'; Heikki Lukkarinen; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Mechanical ventilation; extremely preterm infant; forced oscillation technique; volume targeted ventilation; proportional assist ventilation; phrenic nerve activity; electrical activity of the diaphragm; Pediatrik; Pediatrics;

    Sammanfattning : Extremely low gestational age newborns (ELGANs) i.e. infants born before 28 weeks of gestational age (GA), require respiratory support during their hospital stay, and a majority needs mechanical ventilation (MV) at some time point. LÄS MER