Ahsan Choudhuri

The University of Texas at El Paso

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Norman Love

The University of Texas at El Paso

Md Mahamudur Rahman

The University of Texas at El Paso

ÁF

Ángel Flores-Abad

The University of Texas at El Paso

S. R. Gollahalli

University of Oklahoma

Bidhan Dam

Woodward (United States)

Amelia D. Greig

The University of Texas at El Paso

Joel Quintana

The University of Texas at El Paso

Jorge Camacho

University of Wisconsin–Platteville

Mahesh Subramanya

The University of Texas at El Paso

Mahadi Hasan

The University of Texas at El Paso

Cooperative Institutions

The University of Texas at El Paso

211

Kyushu Institute of Technology

Japan Aerospace Exploration Agency

Marshall Space Flight Center

The University of Texas at Austin

Air Liquide (United States)

The Ohio State University

Bangladesh Council of Scientific and Industrial Research

Consejo Superior de Investigaciones Científicas

University of Oklahoma

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Shapes of Elliptic Methane Laminar Jet Diffusion Flames

Journal of Engineering for Gas Turbines and Power (2004)

Jorge Camacho Ahsan Choudhuri

Buoyant and nonbuoyant shapes of methane flames issued from a 2:1 aspect ratio elliptic tube burner were measured. Nonbuoyant conditions were obtained in the KC-135 microgravity research aircraft operated by NASA’s Johnson Space Center. A mathematical model based on the extended Burke-Schumann flame theory is developed to predict the flame length of an elliptic burner. The model utilizes Roper’s theoretical method for circular burners and extends the analysis for elliptic burners. The predicted flame length using the theoretical model agrees well with experimental measurements. In general for the elliptic burner the nonbuoyant flames are longer than the buoyant flames. However, measured lengths of both buoyant and nonbuoyant flame lengths change proportionally with the volumetric fuel flow rate and support the L vs Q correlation. The maximum flame width measured at buoyant and nonbuoyant conditions also show a proportional relation with the volumetric fuel flow rate. Normalized buoyant and nonbuoyant flame lengths of the elliptic burner correlate (L∕d∝Re) with the jet exit Reynolds number and exhibit a higher slope compared to a circular burner. Normalized flame width data show a power correlation (w∕d=cFrn) with the jet exit Froude number.

Froude number

Gas burner

10.1115/1.2032449

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Increasing Water Vapor Transportation Rates from Lunar Regolith by Utilizing an Ionization Method

ASCEND 2022 (2021)

Amelia D. Greig Nathaniel I. Jurado Priscilla A. Mendoza Emmanuel Negron-Ortiz Zachary Oropeza

Harvesting resources from the lunar regolith is essential for future deep-space human exploration missions. Water is of particular interest as it can be used to support the population in lunar settlements or be separated into hydrogen and oxygen to use as propellants to support onward or return missions from the lunar gateway. Water has been confirmed to exist on the lunar surface, but extraction and collection is challenging. Several thermal mining approaches where regolith is heated causing water vapor to sublimate from the surface are under development. One of the biggest challenges with this approach is the low-pressure environment. Sublimated water vapor exists in the rarefied flow regime and cannot be controlled through standard pressure-driven flow methods. A novel approach to addressing the rarefied water vapor transport challenge is to create electrons to ionize the water vapor that can then be directed to the collector using an electric field. Three approaches to creating ionizing electrons are considered: DC electron source, RF electron source, and DC electron source with magnetic trapping. An analytic model shows that water vapor collection rates can increase by 52%, 372%, and 478% for the DC, RF, and magnetic modes, respectively. Using the ionization transport approach may lead to smaller lunar water mining systems, enabling more efficient harvesting of local resources for future human exploration missions.

Regolith

10.2514/6.2021-4046

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Kinetic Modeling of a Conceptual Hydrogen Production Plant for Regional Hydrogen Resiliency

Safwan Shafquat Afsana Mustari Itul Sumit Chanda Md Ismail Hassan Udoy Anika Tasnim

Abstract The current article explores a conceptual hydrogen (H2) production plant with an integrated gasification combined cycle (IGCC) designed in a commercially available simulation software to meet the auxiliary power requirements of the plant and a portion of the local electricity demand. A kinetic reactor model was used to carry out the gasification reactions. A major goal was to understand the capability of locally available feedstocks in El Paso, TX, such as pecan shells, cotton gin trash, and MSW, in hydrogen production. Both single feedstock gasification and co-gasification (municipal solid waste and pecan shell blend) methods were investigated to observe feed sensitivity to hydrogen production. A process parametric sensitivity analysis is conducted, primarily focusing on equivalence ratio and temperature. Initial results show that a lower equivalence ratio (ER) provided more H2 and CO yield and then decreased as ER increased from 0.18 to 0.36. However, a slightly different trend is seen when cotton gin trash (CGT) is used as feedstock. The sensitivity study found that the highest H2 yield was from pecan shell gasification at 950°C temperature. Additionally, co-gasification of pecan shells and MSW provided better syngas yield results with approximately 31% H2 and 32% CO, respectively, compared to only MSW gasification.

10.1115/imece2024-145911

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Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

Ahsan Choudhuri

Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

Flashback

Flame speed

10.2172/1025558

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An Experimental Investigation on the Heat Transfer Characteristics of Liquid Methane

Adrian Trejo Chance Garcia Ahsan Choudhuri

This paper discusses the heat transfer characteristics of liquid methane (LCH 4) flowing through a cooling channel heated by a Carbo-Thermal Rig. This test apparatus has been developed at the high heat transfer test facility at the Center for Space Exploration Technology Research (cSETR), located at the University of Texas at El Paso (UTEP). It is used for the purpose of simulating the heat load conditions endured in regenerative cooling applications in rocket engines. The facility is designed for working temperatures of up to 650 °C. Fluid flow rates are between 0.2-0.4 kg/s with a maximum operating pressure of 2068 kPa. In addition to ambient testing, experimentation is performed under vacuum conditions (5.5x10 -2 Torr). The overarching goal is to observe and characterize the relationship between the heat transfer and fluid flow behaviors by utilizing multiple temperature measurements along the cooling channel surface and inlet/exit fluid temperatures, as well as flow rate measurements.

10.2514/6.2012-4121

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Citations (8)

Drone Inspection Flight Path Generation from 3D CAD Models: Power Plant Boiler Case Study

AIAA SCITECH 2022 Forum (2020)

Angel Ortega Julio Reyes Muñoz Michael McGee Ahsan Choudhuri Ángel Flores-Abad

Robotic technologies for inspection purposes of large-scale structures have grown in interest. Such technologies are encouraged to reduce the risk in which human operators are involved and to reduce costs due to downtime of the equipment. In the Energy sector, high interest is placed on powerplant components where their correct operation is paramount. Inspired in the synthetic vision systems for aerial vehicles that use three-dimensional space (3D) to provide pilots with clear and intuitive means of understanding their flying environment, here we propose the use of the 3D Computer Aided Design (CAD) model of structural components of a power plant to define an off-line flight path for Unmanned Aerial Vehicles (UAVs). This method is feasible to implement because nowadays the CAD model of structural elements is readily available. Since this work focuses on structural inspection, only the surface characteristics of the model are required. To acquire, analyze and process the 3D model, first, the STL file is produced to obtain surface points and vectors normal to the surface. Later, by introducing other variables such as wall offset and controlled trajectory between each outline and each subsequent layer, the flight path is generated. This method would support efforts where the UAV is required to fly with no GPS available and/or beyond line of sight (BLOS). The effort was conducted using the MATLAB software and the multiple processes involved are discussed in detail. The final trajectory was validated using the Gazebo simulator which employs robust kinematic and dynamic models.

Drone

Downtime

10.2514/6.2020-1091

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Citations (4)

Development of metamaterial based low cost passive wireless temperature sensor

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2014)

Hasanul Karim Mohammad Arif Ishtiaq Shuvo Diego Delfin Han Lin Ahsan Choudhuri

Wireless passive temperature sensors are gaining increasing attention due to the ever-growing need of precise monitoring of temperature in high temperature energy conversion systems such as gas turbines and coal-based power plants. Unfortunately, the harsh environment such as high temperature and corrosive atmosphere present in these systems limits current solutions. In order to alleviate these issues, this paper presents the design, simulation, and manufacturing process of a low cost, passive, and wireless temperature sensor that can withstand high temperature and harsh environment. The temperature sensor was designed following the principle of metamaterials by utilizing Closed Ring Resonators (CRR) embedded in a dielectric matrix. The proposed wireless, passive temperature sensor behaves like an LC circuit that has a resonance frequency that depends on temperature. A full wave electromagnetic solver Ansys Ansoft HFSS was used to perform simulations to determine the optimum dimensions and geometry of the sensor unit. The sensor unit was prepared by conventional powder-binder compression method. Commercially available metal washers were used as CRR structures and Barium Titanate (BTO) was used as the dielectric materials. Response of the fabricated sensor at room temperature was analyzed using a pair of horn antenna connected with a network analyzer.

HFSS

Barium titanate

10.1117/12.2045242

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Analysis of Drag on Non-Spherical Particles in Fluidized Beds

Mario Alberto Ruvalcaba Md Mahamudur Rahman Norman Love Ahsan Choudhuri

Fluidized bed gasifiers are useful for processes where fuels form highly corrosive ash. Most common particles in this type of chemical process are non-spherical. The modeling of these particles can be determined only through the understanding of flow characteristics such as drag coefficient and terminal velocity. In this paper the calculation of drag coefficient of a solid non-spherical particle moving at the terminal velocity is being studied. The numerical approximations are done using the solver FLUENT on a collocated grid. The non-spherical particle shape simulated in this study was elliptical. Experimental drag results are compared to experimental data for validation. The experimental setup was comprised of an elliptical rice particle and a high-speed camera system to record particle movement in the free falling stream to determine the drag coefficient of the non-spherical particle. A 2% error was found between numerical results compared with those found by the theoretical calculation. Results from the drag model varied by 14% from those obtained experimentally.

10.2514/6.2011-5746

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An Experimental Investigation on the Steady State Heat Transfer Characteristics of Liquid Methane

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference (2013)

Adrian Trejo Chance Garcia Ahsan Choudhuri

The steady state heat transfer characteristics of liquid methane (LCH4) under forced convection in a 1.8 mm x 1.8 mm square. This study is intended to understand the cooling characteristics of liquid propellants in cooling channels representative of those associated with regenerative cooled rocket engines at steady state conditions. Due to the limited data concerning the heat transfer characteristics of LCH4, in particular with square channels, a High Heat Flux Test Facility (HHFTF) was developed at the Center for Space Exploration Technology Research (cSETR). The HHFTF is designed to handle cryogenic fluids while maintaining high heat fluxes between 3.3 and 20.0 MW/m 2 . The average Nusselt number (NuD) reaches as high as 336 and average Reynolds numbers (ReD) between 1.9 x 10 4 to 1.6 x 10 5 . A Nusselt number correlation (NuO) used by NASA/Rocketdyne [1] demonstrates an over prediction primarily with Reynolds numbers in the range of 6.0 x 10 4 to 1 x 10 5 . Meanwhile, the majority of the over predictions exist between 1 x 10 5 and 1.1 x 10 5 .

10.2514/6.2013-4145

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Citations (9)

Metal 3D Printing of Low-NOX Fuel Injectors with Integrated Temperature Sensors (Final Technical Report)

Ahsan Choudhuri

This technical report presents the exploration of design and prototyping of an Oxy-fuel injector with integrated temperature sensing capabilities using Additive Manufacturing (AM) technology. The AM process has proven itself as a viable method to fabricate complex shapes for custom-designed metallic components rapidly. The lack of assembly requirements and the virtually unlimited geometrical complexity renders the AM process particularly attractive for fabricating complex energy system components. The unique layer-by-layer fabrication technique allows the embedding of sensors within complex components early in the design process. Sensors can be embedded (without post-production component modifications) in AM-fabricated components through two distinct processes: Stop and Go or Post-Integration. The Stop and Go fabrication process allows sensor placement within a cavity during fabrication; where the process is allowed to continue upon sensor placement. Post-integration process supports selective build of customized compartments for sensors within the part. The Stop and Go process requires an extremely accurate re-alignment of the powder-bed during the restart process. Additionally, metallization and shorting of sensors due to a considerably high temperature of the AM process creates significant fabrication challenges and limit the types of sensors that can be embedded. The Post-Integration of sensors is a practical alternative for components that can be effectively designed and fabricated with pre-built complex sensor compartments without the need for post-production component modifications. The proposed effort aimed at exploring the fabrication of an oxy-fuel injector designed for high-pressure Oxy-Combustion applications (Combustor for Directly Heated Supercritical Power Cycle) with integrated temperature measurement capabilities using the AM technique. Since the current design methodology of injectors is based on conventional fabrication techniques (e.g., multi-step machining and welding processes), a new paradigm of design methodology needs to be developed for their adaptation in the AM fabrication process. One of the most challenging issues addressed in powder bed fusion is the removal of powder from internal channels/cavities as the powder to be removed has been lightly sintered during the fabrication process. In this research, a major task has been assigned to developing and evaluating powder removal techniques that will ultimately be used when removing sintered powder from cavities/channels used for sensor placement. Achieving thorough powder removal will permit the incorporation of intricate cavities, integrated fasteners, or other novel features to incorporate sensors into parts directly post-fabrication – allowing for the novel, AM-based design practices to be developed and employ for sensor integration. The designed injector was initially tested at atmospheric conditions to review its successful operation. The tests were carried out for different firing inputs; with a minimum of 55 kW and a maximum of 275 kW. Later tests were carried out for pressurized conditions between 82 kW to 275 kW firing input. A pressure of 16.35bar was observed in the combustion chamber pressure during the pressurized test of 275 kW firing input; test duration was 15 seconds. Integrated thermocouples within the injector provided temperature data for test operations. The data revealed during the atmospheric condition the injector temperature is almost unaffected by the combustion. However, during the pressurized condition, the injector temperature rapidly up to 205°C within 15 seconds; at a 275 kW firing input.

Rapid Prototyping

Component (thermodynamics)

10.2172/1489120

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