Research Examples

ENGINEERING RESEARCH EXAMPLES Dr. Adonyi SUMMARY • Can you walk, think and chew gum at the same time? Categories of research mixed • TE module R&D examples • How is R&D being performed? (“modus operandi”) • Is R&D a business or a non-profit endeavor? • Conclusions Types of Research, reminder 1. Fundamental: Thinking General: No specific industry Blue-sky, mostly analytical No clear deliverables, only ‘impact’ 2. Applied: Walking Specific industry targeted Mostly experimental Clear deliverables 3. Industrial/commercial: Chewing gum Company specific, implementation Timing of Engineering Research, TE elements 1. Strategic, long-term, PhD - II-VI: high temperature stability of interfaces, improved Figure of Merit 2. Tactical, medium-term, MSc - Marlow/II-VI: microwave welding, improve life 3. Immediate, short-term, BSc - Marlow: NDE of modules  Example: TE Research Methodology Surface Energy Calculations Wettability 1000°C Test Metal Flow Microwave Operating Contact Optimal Characteristics Welding Temperature Angle Coatings, Welded Interface Surface Atmosphere Roughness and Test Roughness  PROBLEM STATEMENT: BSc+MSc+PhD Project Goal JOINT GEOMETRIES • Raise operating temperature of Thermoelectric Modules (TEM’s) to 1000°C • Improve the efficiency and performance for all TEM’s • Replace soldered & brazed joints • Model and validate ceramic-to- metal interface phenomena • Optimize joining technology for future Example PhD level: Wettability Test • Samples prepped using methanol • Surface roughness recorded using profilometer • Heated in Gleeble at 300 °C for 30 seconds • Data collected using optical and thermal cameras • Contact angle found using imaging software Young’s Equation • γSG=γSL+γLGcosθ – γSG= Interfacial energy between solid and gas – γSL = Interfacial energy between solid and gas – γLG = Interfacial energy between solid and gas  Diffusion Background • Material transport by atomic motion • Types – Interdiffusion – Self-diffusion – Impurity diffusion • Mechanisms – Vacancy diffusion – Interstitial diffusion • Fick’s second2 law 𝜕𝜑 𝜕 𝜑 =𝐷 2 𝜕𝑡 𝜕𝑥  COMSOL Modeling Verification Diffusion of Ni into n-type Bi2Te3 0.50 0.40 Concentration Ni 0.30 Diffusion Equation 0.20 COMSOL Experimental Data 0.10 0.00 0.00 2.00 4.00 6.00 Distance from Interface (µm) Example: Level MSc Microwave Welding Outline Purpose • Dielectric Heating • Develop Microwave Welding as a viable process for • High Frequency Induction fabrication of thermoelectric Heating devices • Theory • Heat Transfer Equations – Simultaneous heating methods • Filler Metal Selection to account for varying material properties • Waveguide • Dielectric Heating in TE material • High Frequency heating in metallic coating\filler metal – Significantly shorter period at elevated temperature than oven soldering  Verifying Heating in Waveguide • Both Al paste and Ni coated TE elements heated • No arcing occurred • Demonstrated the need for optimizing waveguide – Heating rate too low – Damage to TE elements Dielectric Heating Ionic Polarization of Sodium Principles Chloride • Ionic Polarization – Electric field causes displacement between ions – Movement in oscillating field generates heat • q̇ E=2πfε0ε”effE2 High Frequency Heating Principles • Lenz’s Law – Current opposes changing emf • Joule effect – P=I2R • Heat Generation – q̇ H=2πfμ0μ”effE2 • Skin Effect 𝜌 𝑑 = 503 𝜇𝑟 𝑓  Frequency • Skin Depth at 2.5GHz – 1.7µm • Average particle size Skin Depth vs Frequency – 22.2µm 3.0 Skind Depth (μm) 2.5 2.0 Aluminum 1.5 Nickel 1.0 Cobalt 0.5 Copper 0.0 Gold 1 10 100 Frequency (GHz)  Heat Transfer • Heat Generation – Dielectric Heating q” • q̇ E=2πfε0ε”effE2 Metallic Filler q̇ H – HFI Heating Metallic • q̇ H=2πfμ0μ”effH2 Coating q̇ H • Heat Transfer Out – q”conv=h(Ts -T∞) q̇ E – q“rad=εσ[(Ts)4-(T∞)4] TE Material Short Term Projects May 20, 2011 NVG TEM Eddy Current Testing • Orientation of Elements within Module – Elements not oriented in the same direction – Scanning is difficult due to orientation NVG TEM Eddy Current Testing • Semi-Automated Setup – Simple G-code written – 2 in/min velocity – 1 MHz probe Impedance scan, “Bad” module NVG TEM Destructive Testing, “Bad” module Solder overflow PRELIMINARY CONCLUSIONS • The three levels of R&D can (and should be) performed simultaneously • There is a continuous improvement cycle and interaction between them • Funding mechanism varies: academic credit, retainer, unrestricted accounts, dedicated accounts How is R&D being perfomed? • Networking, RFP (Request for 1 Proposal) listing, NSF, THECB • Writing Proposal, peer review, 2 gnashing of teeth, budgets • Initial approval, budget and 3 deadline adjustments.  Managing R&D Deliver on time and within budget Setting up Stage teams, training, etc Hiring researchers, purchasing equipment Time Spent CONCLUSIONS • R&D is like any other business: if it does not grow, it dies! • R&D has to be led and managed like any other business • R&D does not produce profit, but generates overhead • R&D has two outputs: quality research and quality graduates