Engineering Commons^™

Droplet Impact And Penetration On Series Of Parallel Tubes, S. Hosseini, A. Dalili, Nasser Ashgriz, S. Chandra

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

Impact and penetration of a liquid droplet on a substrate having a line of parallel capillary openings drilled along its thickness is experimentally studies. Different regimes of droplet penetration are identified. At low impact velocities, the droplet impacts on the substrate, spreads, and penetrates into the substrate mainly due to the capillary action in each tubular hole. At higher impact velocities, the droplet impacts on the substrate, spreads and penetrates due to the droplet inertia, and then penetrates further due to the capillary action. Threshold velocities for liquid penetration into capillary tubes are identified. Two penetration regimes, capillary and inertia …

The Preparation And Properties Of Novel Structural Carbon Foams Derived From Different Mesophase Pitches, Liqiong Yu, Zhihai Feng, Zhen Fan, Qing Kong, Lin Xu

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

As a novel porous multi-functional carbon material, carbon foams have high bulk thermal conductivity and low density, making them as excellent materials for thermal management systems applications, such as heat exchangers, space radiators, and thermal protection systems. In this paper, the carbon foams with high thermal conductivity, derived from three kinds of mesophase pitches, were fabricated by the process of foaming, carbonization and graphitization. The microstructures of the foams were examined by scanning electron microscopy. It was found that the pores were uniformly distributed, and the pore wall thickened with increasing foams’ density. The properties of the foams were studied, …

Effective Solid-To-Fluid Heat Transfer Coefficient In Egs Reservoirs, Xiao-Long Ouyang, Rui-Na Xu, Pei-Xue Jiang

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

The present work developed a three-equation local thermal non-equilibrium model to predict the effective solid-to-fluid heat transfer coefficient in the enhanced geothermal system reservoirs based on the volume averaging method. Due to the high rock-to-fracture size ratio, the solid thermal resistance effect in the internal rocks cannot be neglected in the effective solid-to-fluid heat transfer coefficient. The present three-equation local thermal non-equilibrium model can consider the dynamic variation of the solid thermal resistance in transient heat transfer by introducing the penetration temperature difference. The model was validated by comparison with pore-scale numerical simulations and macro-scale LTNE model numerical simulations. The …

Improved Permeability Prediction For Heterogeneous Porous Media By Bundle-Of-Leaky-Tubes With Cross-Flow Model, Faruk Civan

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

An inherently limiting assumption of the Kozeny-Carman equation of permeability is not allowing interaction across the parallel flow through a bundle of tubes model. While this condition can be observed for flow through sufficiently high porosity homogeneous porous media, the Kozeny-Carman equation cannot represent the permeability of low porosity heterogeneous porous media. This paper presents a modeling of flow through a leaky-flow tube allowing interactions with flow occurring in other flow tubes in a bundle of tubes model of porous media. Then, the effect of such interactions is taken into account by incorporating the pore connectivity by means of the …

Porous Structures Used As Flameproof Pressure Relief Elements A Novel Approach Of Flameless Venting, Julia Hornig, Detlev Markus, Martin Thedens

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

Here, a novel approach to flameless venting is presented, which offers the possibility of improving the design of flameproof enclosures without reducing any safety aspects. This approach is based on the integration of porous structures – such as traditional sintered metals or sintered metal fibers – into the enclosure walls acting as venting and flame-quenching elements. It is shown that proper use of these structures can enormously decrease the maximum explosion pressure while safely avoiding flame transmissions, even for a large number of consecutive internal explosions. However, the transmission of a gas explosion through porous structures is a transient and …

Keynote – Nonlinear Natural Convection In Porous Media And The Collapse Of The Wave Function, Peter Vadasz

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

A short review of the problem of nonlinear natural convection in a fluid saturated porous layer heated from below is presented. When the conditions for the onset of convection are met a wave function is obtained as the solution of the linearized equations expressed in terms of a Fourier expansion. Only one mode of this expansion survives at the onset of convection, a result that can be seen as the "Collapse of the Wave function" in a very similar fashion as in quantum mechanics, although the explanations of the latter are very distinct from the ones in quantum mechanics. The …

Effect Of Bondcoat Roughness On Lifetime Of Aps-Tbc Systems In Dry And Wet Gases, W.J. Quadakkers, D. Naumeko, P. Mor, W. Nowak, L. Singheiser

Thermal Barrier Coatings IV

Low pressure plasma spraying (LPPS) is a process commonly used for deposition of MCrAlY (M=Ni,Co) bondcoats for air plasma spray thermal barrier coatings (APS-TBCs). LPPS produces bondcoats with a high roughness and good oxidation resistance, which are known to play a key role for long lifetimes of APS-TBC’s. An alternative process for the bondcoat deposition is high velocity oxy-fuel (HVOF), which is substantially cheaper than LPPS but even with well optimized spraying parameters generates intrinsically lower bondcoat roughness. In the present work it is shown that a bi-layer MCrAlY-bondcoat consisting of an HVOF-base layer and an upper, thin APS-flashcoat of …

Application Of Eq Bond Coat To Eb-Pvd Tbc Systems, Kazuhide Matsumoto, Kyoko Kawagishi, Yutaka Koizumi, Hiroshi Harada

Thermal Barrier Coatings IV

To prevent the formation of SRZ in the log-time high-temperature exposure of the turbine blades, thermodynamically equilibrium phase such as gamma-prime phase of the substrate is use as an oxidation-resistant bond coat. The previous study clarified that this EQ coating shows excellent interface stability and it does not degrade mechanical strength due to the SRZ formation. In this study, TBC life test of EB-PVD ceramics coated EQ coating is investigated with other conventional MCrAlY coatings. The 4th and 5th generation superalloys are used for substrates. About 150 μm thick of EQ coating, conventional NiCoCrAlY and CoNiCrAlY coating are deposited by …

The Role Of Reactive Elements In Improving The Cyclic Oxidation Performance Of Β- Nial Coatings, Hongbo Guo, Hui Peng, Dongqing Li, Tian Zhang, Shengkai Gong

Thermal Barrier Coatings IV

the bond coat in thermal barrier coating (TBC) system. However, the oxide scale grown on NiAl spalls readily during high-temperature cyclic oxidation. Reactive elements (REs) as well as their oxides dispersions were investigated to improve the cyclic oxidation performance. In this work, the effects of several REs on the adherence of Al2O3/NiAl interface were investigated by first principles theory calculations and experiments. We find that the solubility of the REs in NiAl alloy arrive at an order of Hf >Zr>Dy>Y>La, all the REs exhibit an affinity for sulfur, with an order of La>Dy>Y>Zr>Hf, …

A Recent History Of Thermal Barrier Coatings For Aero-Propulsion Applications, Brian Hazel, Michael J. Maloney

Thermal Barrier Coatings IV

Thermal barrier coatings for aero-propulsion operation have been in use since the 1960s. These thermal barrier coatings are composed of an oxidation resistant metallic base layer and a thermally resistant ceramic top layer. The development and implementation of advances in both the metallic base and the ceramic top layer will be explored. The evolution has included performance and durability improvements, process advances, and understanding and evolution of failure modes. More recent efforts have focus on future challenges for thermal barrier coatings to meet ever increasing operating temperature demands of future applications.

Potential Impacts Of Alternative Fuels On The Evolution And Stability Of Turbine Hot- Section Materials, Daniel Mumm, Timothy Montalbano, Matthew Sullivan

Thermal Barrier Coatings IV

This talk will provide an overview of a research program focused on evaluating the potential impacts of alternative fuels (coal-derived syngas, high-hydrogen content fuels, bio-derived synthetics) on the degradation of hot-section materials through accelerated attack of protective thermally grown oxides (TGOs) and thermal barrier coating (TBC) systems. A primary focus is the role of elevated water vapor levels, volatility, and vapor phase transport processes on the evolution of TGO and TBC systems. Materials exposure studies will be described that demonstrate that differing simulated combustion environments affect both the growth rate and the stability of the resulting thermally grown oxides. In …

On The Behavior Of Titanium Within Thermal Barrier Coatings And Its Influence On Residual Stress Within The Tgo, Robbie J. Bennett, Ian Edmonds, Neil Jones, Catherine Rae

Thermal Barrier Coatings IV

This research focuses on analysing the interaction between three commercially used diffusion coatings and a nickel based superalloy CMSX-4. The coatings applied are alumide, Pt-alumide and Pt-modifed γ/γ′. The research has two main themes, firstly diffusion and secondly oxidation. Results of quantitative EPMA show that titanium diffusion towards the surface varies between coatings, and has a strong correlation with the use of platinum within coatings. The concentrations of Ti within Pt-aluminide coatings after 100 hours oxidation in air at 1100°C were found to be twice as high as those within the plain aluminised CMSX-4 samples. Furthermore uphill diffusion of Ti …

The Effect Of Environment And Superalloy Composition On Tbc Lifetime, Bruce Pint, Kinga Unocic, Michael Lance, J. Allen Haynes

Thermal Barrier Coatings IV

While the water vapor content of the combustion gas in natural gas-fired land based turbines is ~10%, it can be 20-85% with coal-derived (syngas or H2) fuels or innovative turbine concepts for more efficient carbon capture. Additional concepts envisage working fluids with high CO2 contents to facilitate carbon capture and sequestration. Also, for land-based, power-generation turbines, there is industry interest in reducing alloy costs by decreasing the superalloy Re content, either by developing new alloys or employing earlier generation superalloys. To investigate the effects of these variables on thermal barrier coating (TBC) lifetime, furnace cycling tests (1h cycles) were performed …

High-Temperature Ceramic Coatings Used In Aero Engine Environments, David Rickerby, Paul Morrell, Matthew Hancock

Thermal Barrier Coatings IV

This paper reviews the role of ceramic coatings technology in the hot sections of modern gas turbine engines by contrasting the role of surface engineering and coatings away from secondary reliance (i.e. the coating extending the life of the component and when the coating is lost or fails there is still an appreciable remnant life of the component) to prime reliance where the failure of the coating would result in a rapid failure of the component. To illustrate this change in design philosophy, the coating systems deployed in the HP turbine module in both shrouded and unshrouded configurations are discussed …

Fate And Transport Of Nanohybrids In Subsurface Media For Oil Field Applications, M.J. Kadhum, D.P. Swatske, J.H. Harwell, D.E. Resasco, B.J. Shiau

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

Interfacially active carbon nanotube hybrids have potential to be used in reservoir development applications. Carbon nanotubes hybrids (CNT) can act as carriers for catalytic nanoparticles into regions far inside the reservoir; they have the ability to stabilize water/oil interface in emulsions or can be used as contrast agents or sensors. One of the main challenges for successful utilization of these nanoparticles is the difficulty associated with stabilizing their dispersions and propagating them through the wellbore rock or deep inside the reservoir in harsh reservoir conditions of salinity and temperature. In this work, CNT were dispersed in high salinity brine using …

Particles Migrating And Plugging Mechanism In Loosen Sandstone Heavy Oil Reservoir And The Strategy Of Production With Moderate Sanding, Yiting Xie, Zhaohui Chen, Fujie Sun

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

Fine rock particles is easy to be suspended and carried in loosen sandstone heavy oil reservoir due to the higher density and viscosity of heavy oil. The sand particles settle down, bridge and clog in pore and throat, as the result, the filtration resistance in reservoir will be redistributed. It significantly impacts on the well productivity. In this paper, the process of sand particles transporting and clogging in tunnels of rock is observed utilizing a microscopic visualization model with the unconsolidated sandpack. Furthermore, the mechanism of fine particles migration and clogging and the effects to percolation capacity of porous medium …

The Effect Of Exposure Variables On The Development Of Alumina Scales, Gerry Meier

Thermal Barrier Coatings IV

The early development of an adherent, slowly-growing α-alumina film on the bond coat is a critical factor in the life of a thermal barrier coating system. This presentation will include results of recent experiments at the University of Pittsburgh and reanalysis of older data from the literature on the selective oxidation of aluminum from Ni-base alloys. The following aspects of alumina scale establishment will be addressed: • The manner by which alloy composition affects the kinetics and mechanism of the transition of alumina from the θ to the α polymorph. • The influence of the θ to α transition on …

Design Constraints And Higher Temperature Intermetallic Bond Coatings, T.M. Pollock, D. Jorgensen, R.W. Jackson, M. He, A. Suzuki, D. Lipkin

Thermal Barrier Coatings IV

Bond coat interlayers in thermal barrier coating (TBC) systems must perform reliably in the complex thermal, chemical and mechanical environment of the turbine engine. To achieve higher temperatures and /or longer cyclic lives, a spectrum of intrinsic failure modes must be suppressed. Failure may occur at the bond coat – thermally grown oxide (TGO) interface, at the TGO-TBC interface or by oxidation-enhanced propagation of cracks from the coating into the substrate. Models for the failure processes suggest that bond coatings should possess improved high temperature strength (creep resistance), low oxide growth stresses and high interfacial toughnesses. Oxide growth stresses have …

Cold Spray Bond Coats Structure And Oxidation Behavior, A. Barth, S. Kudapa, W. Wong, K. Onizawa

Thermal Barrier Coatings IV

No abstract provided.

Preface, Engineering Conferences International

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

No abstract provided.

Program, Engineering Conferences International

5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry

No abstract provided.

Program, Franco Berruti

Thermal Barrier Coatings IV

No abstract provided.

Analysis Of Critical Behavior In Magnetic Materials, Dustin David Belyea

USF Tampa Graduate Theses and Dissertations

This work contains a broad study of a variety of magnetic materials undergoing second order phase transitions. In general this leads to an overall increase in information and analytical methods to further the field of magnetocalorics. Specifically, critical aspects of magnetocaloric materials were compared within systems in relation to structure, stoichiometry, magnetic minority phases and magnetic contaminants. Detailed analyses were developed to quantify techniques which were in the past used mainly in a qualitative way, leading to a more complete understanding of how critical phenomena impacts the magnetocaloric response.

A Comparative Study Of Commercially Available Comfort Fabrics, Melinda Elizabeth Finnie

Master's Theses and Doctoral Dissertations

The comfort fabric market continues to grow and become more competitive. Consumers expect their active wear to deliver performance beyond simply being a barrier between their body and the environment. Textile manufacturers have taken notice, and there is a wide range of comfort fabrics on the market. This research tests fabric samples from leading comfort fabric technologies: phase change materials, nanotechnology, modified fiber structure and blends, as well as the original comfort fiber, cotton. The most widely recognized comfort fabric properties concern the thermal and moisture management of a fabric. Using a guarded sweating hot plate, standardized test methods, and …

Creating A Stem Identity: Investment With Return, Janet Callahan, Patricia Pyke, Susan Shadle, R. Eric Landrum

Materials Science and Engineering Faculty Publications and Presentations

Establishing a strong STEM (science, technology, engineering and mathematics) identity at Boise State University, a metropolitan campus with approximately 3,655 undergraduate STEM students and a total undergraduate enrollment of approximately 19,042 (16,136 FTE) has been an important step toward creating a climate conducive to facilitating fundamental change. Examples of such change include building collaborations among faculty within and across departments, establishing the identity of students as part of a community beyond their chosen major, improving the efficiency and effectiveness of university systems, and perhaps most importantly, developing a framework to think deliberately about ways to effect change. This paper is …

Stress Analysis For Chip Scale Packages With Embedded Active Devices Under Thermal Cycling, Hyunwook Yeo

Dissertations and Theses

One of the main challenges in the electronics manufacturing and packaging development is how to integrate more functions inside the same or even smaller size. To meet the demand for higher integration, the interest toward passive and active component embedding has been increasing during the past few years. One of the main reasons for the growing interest toward embedded active components, in addition to demand for higher packaging density, is the need for better electrical performance of the component assemblies. However, it is little known how embedded IC and passives affect the reliability of IC packaging.

Solder joints have been …

Experimental Investigation Of Lateral Cyclic Behavior Of Wood-Based Screen-Grid Insulated Concrete Form Walls, John Stuart Garth

Dissertations and Theses

Insulated concrete forms (ICFs) are green building components that are primarily used for residential wall construction. Unlike most polystyrene based ICF variants, the Faswall ICFs used in these experiments were significantly denser because they were made from recycled wood particles and cement. The current design approach for structures constructed with this type of wall form only allows the designer to consider the contribution of the reinforced concrete cores. Previous research has shown that this approach may be conservative. This project experimentally evaluated the lateral structural response of these types of grid ICF walls under increasing amplitude of in-plane cyclic loading. …

Biomechanical Properties Of Hemlocks: A Novel Approach To Evaluating Physical Barriers Of The Plant-Insect Interface And Resistance To A Phloem-Feeding Herbivore, Paul Ayayee, Fuqian Yang, Lynne K. Rieske

Entomology Faculty Publications

Micromechanical properties that help mediate herbivore access may be particularly important when considering herbivorous insects that feed with piercing-sucking stylets. We used microindentation to quantify the micromechanical properties of hemlock, Tsuga spp., to quantify the hardness of the feeding site of the invasive hemlock woolly adelgid, Adelges tsugae. We measured hardness of the hemlock leaf cushion, the stylet insertion point of the adelgid, across four seasons in a 1 y period for four hemlock species growing in a common garden, including eastern, western, mountain, and northern Japanese hemlocks. Leaf cushion hardness was highest in the fall and winter and …

Influence Of Grain Size And Widmanstätten Colonies On Variability Of Tensile Properties Of Forged Ti-6al-4v, Blake T. Gaspar

Master's Theses

When testing forgings for specifications, it was found that some parts did not meet the requirements for mechanical properties. This triggered an investigation into two of the parts from the lot that did not meet specification. The ultimate reason for failure was due to lower than necessary yield strength and ultimate tensile strength values, as well as unwanted variability between regions of the part. Therefore, samples of the regions were tensile tested to determine the differences that existed in yield strength, ultimate tensile strength, and elongation. After tensile testing, quantitative metallography and fractography were conducted to identify aspects of the …

An Investigation Into The Properties And Fabrication Methods Of Thermoplastic Composites, Ann E. Livingston-Peters

Master's Theses

As applications for thermoplastic composites increase, the understanding of their properties become more important. Fabrication methods for thermoplastic composites continually improve to match designs specifications. These advanced thermoplastics have begun to show an improvement in mechanical properties over those found in thermoset composites commonly used in industry. Polyaryletherketones (PEK) have high service temperatures, good mechanical properties, and improved processing capabilities compared to thermoplastics used in the past making them important to the aerospace industry. The wide range of types of PEK make them suitable for a variety of applications, but selection of specific chemistries, processing parameters, and composite stack-ups determine …