Inverse Design of Functional Surfaces for Prescribed Simple and Complex Flow Characteristics

In recent years, bio-inspired designs have gained industrial popularity as innovation drivers. Optimum process and design generate greater value such as low fuel cost, low operating cost, low carbon emissions etc. Bio-inspired functional surfaces can be key solutions to unlock these value potentials. The functional surfaces can be employed to generate desired flow characteristics resulting in optimum design and process performance. The functional surfaces can provide optimised solutions by better flow control within flow handling systems. One of the major advantages of bio-inspired functional surfaces is its geometrical simplicity and the resultant major flow effects that might be produced. These flow effects, although produced at immediate local vicinity within the geometry, can potentially bring global flow behaviour change. Stacked discs within multistage continuous resistance trim, an integral part of globe type control valve, can be envisaged as functional surface. Local flow effects in trim geometrical features vicinity can potentially be precursor to global undesirable effects such as cavitation, noise, vibration etc. Functional surface design thus become imperative for globe type control valve efficient performance.

In this thesis, advanced numerical and computational techniques have been employed. Mesoscopic approach is adopted to compute simple flow characteristics while continuum approach is adopted to compute complex flow characteristics. Furthermore, results computed are integrated into a framework. The framework principally links flow features to geometrical features for inverse design process.

The thesis focuses on quantitative and qualitative geometrical effects on flow behaviour by analysing developed equations. Modal analysis of design space computes governing flow features and resulting flow sensing locations. Flow features and their corresponding mathematical contribution within inverse design process is further analysed. As a result, optimised modal selection criterion is developed for considered cases. Consequently, inverse design environment for functional surfaces containing simple discontinuous geometry structure is developed for identified subspace. Furthermore, inverse design framework for functional surfaces containing simple discontinuous geometry structure is developed for multistage continuous resistance trim.