This thesis, which has been carried out at the department of research and development at Cobham Antenna Systems, comprises the development of a fluid rotary joint (FRJ) prototype and shall provide a thorough insight in relevant design aspects. Based on input parameters and objectives derived from an actual Cobham project, the possibility of manufacturing a fluid rotary joint in-house has been investigated. A rotary joint is sub-system built up by modules linking signal transmission between the stationary and rotating parts of a microwave communication system, typically a rotating radar antenna. High power may generate a need of liquid cooling, i.e. a need of a fluid rotary joint module enabling connection of the up- and downstream of a recirculating cooling system, independent of antenna rotation and with minimal leakage. The typical FRJ features a bearing supported rotor mounted with a number of rotary seals inside a casing, referred to as stator, with channels guiding fluid from one to the other. Key objectives of the design are the flow channel configuration and flow performance relative geometrical size and structural integrity. As a result of the comprehensive pre-study three FRJ concepts were created and evaluated based on a customer requirement specification. The most advantageous design, in terms of e.g. manufacturability and flow performance potential, a multi-channel rotor design with mechanical face seals, was selected for further development. The CAD models were created in Solid Edge ST5, evaluated using FEM-analysis in ANSYS Workbench 14.5 and CFD analysis in ANSYS Fluent. The resulting prototype design features wide internal channels, a generous centre bore clearance equivalent to a diameter of 58 mm, robust mechanical face seals and a sturdy stainless steel stator and rotor design with a total weight below 29.2 kg. With a total pressure loss per channel of less than 0.0065 MPa at the specified mass flow rate of 1.5 kg/s the module are capable of mass flow rates up to 2.5 kg/s until reaching the specified maximum pressure loss of 0.02 MPa. Keywords: Rotary union, Rotary coupling, Flow loss, FRJ, RJ / Detta examensarbete, utfört under avdelningen för forskning och utveckling hos Cobham Antenna Systems, består av utvecklingen av en roterskarvsprototyp avsedd för vätskor och ska tillhandahålla en utförlig inblick kring faktorer relevanta för dess konfiguration. Utifrån ingående konstruktionskriterier och målsättningar, hämtade ur ett befintligt projekt hos Cobham, har möjligheterna för att utveckla och tillverka en fluidskarv inom företaget utretts. En roterskarv är ett delsystem uppbyggt av moduler som länkar signalsändningar mellan de stationära och roterande delarna i ett mikrovågskommunikationssystem, typiskt en roterande radarantenn. Med höga effekter kan behovet av vätskekylning uppstå, det vill säga ett behov av en roterskarvsmodul med kanaler som sammanbinder ett slutet kylsystems upp- och nedflöden oberoende antennrotation och med minimalt läckage. Generellt består en sådan fluidskarv av en lagrad rotor monterad i ett hus, kallad stator, vars interna kanaler sammanbinds genom rotationstätningar. Kanalernas utformning och flödeskapacitet relativt fysisk storlek och strukturell integritet anses vara avgörande. Som resultat av den omfattande förstudien baserat på kundkrav skapades tre fluidskarvskoncept som sedan utvärderades. Konceptet som ansågs mest lämpat för vidareutveckling, utifrån bland annat tillverkningsmöjlighet och flödeskapacitet, består av en flerkanalig rotor primärt tätad av tåliga mekaniska plantätningar. CAD-modeller skapades i Solid Edge ST5, utvärderades med hjälp av FEM-analys i ANSYS Workbench 14.5 och CFD-analys i ANSYS Fluent. Vidareutvecklingen resulterade i en prototyp med vida kanaler, en rymlig centrumöppning motsvarande en diamater på 58 mm, robusta mekaniska plantätningar och en stadig design tillverkad i rostfritt stål med en totalvikt under 29.2 kg. Med en tryckförlust på 0.0065 MPa per kanal vid det specificerade massflödet 1.5 kg/s klarar fluidskarven massflöden upp till 2.5 kg/s tills det att den angivna maximala tryckförlusten på 0.02 MPa uppnås. Nyckelord: Vätskeroterskarv, Vätskeroterstycke, Svivel, Roterstycke, Tryckförlust

The main objective of this master thesis is to implement the numerical modelling of the confluence of streams in the Tee-junction using Fluent CFD software. Modelling is carried out for different ratios of flow rates in steady flow. Calculations are evaluated, using a new mathematical model, by curves of loss coefficients. Furthermore, the influence of the selected type of the mesh in geometry on results from numerical modelling of flow is examined. Geometry of the Tee-junction is created in Gambit software. Finally, the results obtained from numerical modelling are confronted with results from an experiment.

This Master’s thesis investigates the flow in sealing gaps of impeller within pumps and turbines. Sealing gaps are installed to improve the volumetric efficiency in this type of fluid machinery. Despite present extensive research this subject has not been entirely documented and the thesis’ aim is to improve our knowledge in this matter. At the beginning, the practical experiment is used in order to establish appropriate numerical description of flow in seals and to calibrate software FLUENT. In chapter five, the thesis analyses the influence of seal design on volumetric efficiency of pumps and turbines and defines its optimal construction to improve the efficiency. The thesis then examines the effect of rotor eccentricity on flow properties, flow rate and pressure distribution within the sealing gap. In the last section, through chapters six to eight, the flow results provided by numerical solution in FLUENT and selected analytical equations, or their modified forms, are being discussed. The degree of correspondence between the results is also studied.

This work seeks to illustrate the potential benefits afforded by implementing aspects of fluid dynamics, especially the latest computational fluid dynamics (CFD) modeling approach, through numerical experimentation and the traditional discipline of physical experimentation to improve the calibration of the severe reactor accident analysis code, MELCOR, in one of several spent fuel pool (SFP) complete loss-of-coolant accident (LOCA) scenarios. While the scope of experimental work performed by Sandia National Laboratories (SNL) extends well beyond that which is reasonably addressed by our allotted resources and computational time in accordance with initial project allocations to complete the report, these simulated case trials produced a significant array of supplementary high-fidelity solutions and hydraulic flow-field data in support of SNL research objectives. Results contained herein show FLUENT CFD model representations of a 9x9 BWR fuel assembly in conditions corresponding to a complete loss-of-coolant accident scenario. In addition to the CFD model developments, a MATLAB based control-volume model was constructed to independently assess the 9x9 BWR fuel assembly under similar accident scenarios. The data produced from this work show that FLUENT CFD models are capable of resolving complex flow fields within a BWR fuel assembly in the realm of buoyancy-induced mass flow rates and that characteristic hydraulic parameters from such CFD simulations (or physical experiments) are reasonably employed in corresponding constitutive correlations for developing simplified numerical models of comparable solution accuracy. / text