Radial inflow turbine meshing rev. 1

This report describes meshing utilities to support the mesh generation for Radial Inflow Turbines. This includes two tools: (a) parameterised mesh generator for Nozzle Guide Vanes; (b) a geometry and mesh generation tool for turbine rotors. A key feature of the turbine rotor mesh and geometry generation tool is that it allows a parametric definition of the geometry based on properties of the aerodynamic passage. For example desired flow direction and evolution of flow area. This is in contrast to alternative methods, which start by defining the physical features of the rotor (e.g. hub and shroud shape), in which case the aerodynamic passage becomes and output. In addition to providing the description of the two tools, usage instructions and examples are provided

pfow.py a potential flow solver and visualizer

pflow.py is a simple teaching and analysis tool for 2-D Potential Flows. It is a collection of code, that allows the construction of simple flow fields that meet the Potential Flow governing Equations. A range of plotting and visulisation tools are included

Code for the design and evaluation of heat exchangers for complex fluids

This report describes a quasi 1-D code that can be used for the design and evaluation of heat exchangers operating with ideal fluid, ideal gases and real gases. For a given heat exchanger defined by heat exchanger type, a range of variables defining the geometry of the heat exchangers, selected heat transfer correlations and selected pressure drop correlation the exchanger performance is evaluated. Employing a fixed heat exchanger geometry allows the performance of a given heat exchanger to be evaluated as fluid boundary conditions (massflow, inlet temperature, inlet pressure) change in both heat transfer channels. In the first instance this allows change in heat exchanger performance for a given heat exchanger to be evaluated across a range of operating conditions. Furthermore this can be used to appropriately size a heat exchanger that is required to operate at a number of conditions

Effect of Vortex-injection Interaction on Wall Heat Transfer in a Flat Plate and Fin Corner Geometry

More flexible and economical access to space is achievable using hypersonic air-breathing propulsion. One of the main challenges for hypersonic air-breathing propulsion is reaching high combustion efficiency within the short residence time of the flow in the engine. Lengthening the combustor is not a viable option due to its many drawbacks, and the use of hypermixers or strut injectors increases mixing efficiency at the cost of increasing losses and heat load. On the contrary, inlet-generated vortices are an intrinsic feature of many scramjet inlets, and can be used to enhance mixing, incurring minimal losses and heat load increase. A previous computational study used a canonical geometry consisting of a flat plate with a fin at different deflection angles to investigate the ability of inlet-generated vortices to enhance the mixing rate. Significant increases in mixing rate were obtained due to the vortex-fuel plume interaction. The flow conditions were equivalent to those found in a rectangular-to-elliptical shape transition scramjet inlet at a Mach 12, 50 kPa constant dynamic pressure trajectory. Despite the minimal heat load increase of this approach, characterization of the vortex-fuel plume interaction effect on the wall heat transfer is required. In this work, the previous study is extended, describing the effect of the vortex-fuel plume interaction on wall heat transfer. Heat flux in the vicinity of the porthole injector reaches 200 % compared to the baseline case with no vortex interaction. Moreover, the injection bow shock affects the corner region, creating pockets of heat flux up to 75 % larger than the unaffected region. Additionally, the evolution of the fuel plume downstream of the injector location is investigated, describing the relationship between local maxima and minima of heat flux, and the location of the fuel on the wall surface. This relationship can be exploited in experimental data acquisition to obtain the fuel location from heat flux data. The viability of this experimental approach is explored using computational data, confirming that through careful sensor placement, position measurements with an accuracy higher than ±5 mm can be achieved

Design approach for maximising contacting filament seal performance retention

Good sealing is a key requirement for modern efficient turbomachinery such as steam and gas turbines. A class of seals that promise better performance, compared to conventional labyrinth seals, are contacting filament seals such as brush, leaf, or finger seal. When new, these filament seals offer better performance; however, if poorly designed they wear excessively, resulting in leakages higher than a comparable labyrinth seal. This paper outlines a design methodology for selecting ideal contacting filament seal properties for a given operating cycle or set of operating cycles. Following this approach ensures the seal performs well, the seal retains its performance, and performance is retained if the operating cycle is altered. In the approach, the seals are described by four generic properties (stiffness, blow-down, cross-coupling, and build clearance), which are then used for a performance evaluation based on a number of test cycles. Once the ideal seal properties for a given operating cycle have been identified, a seal to match these can be designed. The approach is evaluated with a generic gas turbine cycle and recommendations for ideal contacting filament seal properties for this cycle are made

Maximizing contacting filament seal performance retention

The initial superior performance of contacting filament seals compared to traditional seals such as labyrinth seals has been well reported in the literature. A challenge that remains for these seals is ensuring that this performance advantage is retained throughout their operating life, especially if there is uncertainty in the operating cycle. In the current paper, a seal model based on generic seal characteristics is used to explore the relationships between these characteristics, the seal performance, and the seal performance retention. Using this approach seal characteristics are identified that result in a seal that performs well and maintains performance for a given operating cycle. In addition it is demonstrated that the performance and performance retention is maintained even if the seal operating conditions are altered significantly, implying that these seals are more robust also