Research Statement for Kiran Siddappaji

Renewable energy applications (wind, tides and waves), efficient and novel designs for energy conversiondevices using thermodynamics, computational fluid dynamics (CFD), turbomachinery and wind turbinedesign principles, computational methods, better flow visualization tools and CFD solvers are my researchinterests.

Clean energy consumption is the environmentally responsible way of life. Reduction of green housegases at a global scale must be the focus of an engineering solution. After successfully defending my PhDdissertation proposal on “High Efficiency and Cost-Effective Hydrokinetic Turbines”, I am one step closerto graduation. Higher speed winds over the oceans and lakes can be harnessed to produce electric powerusing a sail and parasail driven hydrofoil boats equipped with hydrokinetic turbines (HKTs) called EnergyShip [2] as shown in Figure 1. As the watercraft moves forward, the HKT starts spinning and the generatorconnected to the shaft produces electricity and is used to split water through electrolysis into oxygen andhydrogen which can be stored as fuel and shipped ashore. Optimizing traditional and novel hydrokineticturbines to extract maximum power is my goal. The higher density of the water is advantageous in creatingsmall sized turbines as compared to the wind turbines for the same power rating as shown in Figure 1 whichcompares a 4 kW HKT at 57.55 % efficiency (97.1% of theoretical limit) at flow speed of 6 m/s to an iPhone5 model [1]. The results also prove that counter rotating turbines as shown in Figure 1 improves the totalpower extraction.

Figure 1: Energy Ship [2]; 4kW HKT compared with iPhone 5 model [1]; Single and Counter Rotating HKTs.

Analyzing Open Rotors (unducted counter rotating propfan) using CFD tools is how I started my researchcareer and realized the importance of designing blade geometries and their effect on the efficiency of theenergy conversion device as shown in Figure 3 and the results were presented at DCASS 2010. For myMaster’s research, I created a general parametric blade geometry design tool. The robust tool expeditedthe process of design, analysis and can be included in an automated optimization loop with minimal CADinteraction. Several designs created are shown in Figure 2. Apart from using it in any design-analysisresearch process, the tool is also used extensively in designing novel ideas, Turbomachinery Flows class andsenior engine design projects. It is modular and more features are being added constantly and is freelyavailable at http://gtsl.ase.uc.edu/3DBGB/.

Figure 2: Various blade designs and maple seed and some 3D printed in plastic and metal.

Reverse engineered NREL wind turbine as shown in Figure 3 and created new designs with winglets toanalyze the complex 3D flow physics as a first step into renewable energy applications. Design optimizationis very crucial in learning the trade-offs and obtaining a design with optimum objective function. I was part

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of various design teams whose main goal was to optimize a high pressure compressor and booster flowpathwhich was a NASA funded Multi-Disciplinary Optimization project; transonic fan blade design and laterstage rotor of a high pressure compressor. Ensuring the mechanical strength of these designs were also partof the goal achieved. 5 peer reviewed papers were published on these results and presented as author andco-author subsequently in ASME Turbo Expo 2010, 2011 (2 papers), 2012 and 2014. Currently assisting aproject on tip clearance effects due to novel split tip geometry of a high pressure compressor.

Worked on modifying a 1-D CFD tool and making it available on several platforms which got me in-terested in CFD techniques and tool development. Real world flows are unsteady and time consuming toanalyze. Hence, faster and smarter design-analysis tools are needed to understand this complex phenomenon.Designed unsteady turbines as shown in Figure 3 for a Pulse Detonation Engine (PDE) as part of a DARPAfunded project in collaboration with a company called Illinois Rocstar, where I implemented harmonic bal-ance method for turbomachinery unsteady calculations using a Discontinuous Galerkin discretization schemebased 2D solver, both techniques developed by my colleagues. Designed a modular mesher which can beadded to the geometry tool and handle a wide variety of blading arrangements. The results were presentedat DCASS 2014. I am also part of a CFD design-analysis project of a falling maple seed in order to mimicthe nature as shown in Figure 2 and design better wind turbines.

Figure 3: Contours of relative flow angle for Open Rotor; Static Pressure (Ps) iso-surface for an NREL wind turbine; Machof a turbine with shocks; Entropy for 1 stage unsteady turbine behind a PDE; Ps with relative flow velocity vectors for a 4 kWHKT at mid span.

Building prototypes, testing the designs and manufacturing them is the ultimate goal of any CFD design-analysis process. Supervised several undergraduate senior design teams in building thrust vector device,exhaust driven fan design, power extraction from exhaust of a small scale jet engine and novel nozzle designsas part of University level competitions organized by the Wright-Patterson Air Force Base, Dayton. Thiswas a wonderful experience in learning the manufacturing methods and the cost analysis of a prototype.

With all the knowledge and experience gained by my previous research endeavors, I chose to designefficient and cost-effective hydrokinetic turbines as my PhD dissertation topic. The electricity generationusing HKTs dragged behind a watercraft is innovative and a challenging process with promising results andencouraging to pursue further. Some of the results have been presented at Mech-Aero 2014 conference anda paper is peer reviewed and accepted for publishing in ASME Turbo Expo 2015. Exploring novel designsof the hydrokinetic turbines to improve their performance is part of my future work and I strongly believethat this will be a game changer in renewable energy application.

References[1] GrabCAD. Iphone 5 cad model, http://grabcad.com/library/iphone-5-for-case-design-and-photo-

rendering. http://grabcad.com/library/iphone-5-for-case-design-and-photo-rendering.

[2] Mark G. Turner. Power production using high-altitude and surface winds over the oceans, doe : Tier 1proposal for open-topic and energy capture above 500 feet concepts. June 2014.

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