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Loutzenhiser, Peter G.

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    Georgia Tech | Gen3 CSP Mechanical and Radiative Property Database
    (Georgia Institute of Technology, 2022) Loutzenhiser, Peter G. ; Ranjan, Devesh ; Zhang, Zhuomin ; Schrader, Andrew J. ; Pathikonda, Gokul ; Brooks, Joshua ; Bagepali, Malavika ; Chuyang, Chen ; Jeong, Shin Young ; Yarrington, Justin D. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    The focus of this work is to systematically characterize the heat transfer and flow properties for particulate (granular) flows at elevated temperatures up to 800 °C. This work is intended to address a serious gap within the field related to the understanding and modeling of particulate flow behavior and the related heat transfer at different temperatures, which directly correspond to the operating points of concentrated solar power applications that use particles for heat storage. These objectives will be accomplished using a combination of fundamental experimental measurements, modeling, and simplified flow experimentations over a range of temperatures. Ceramic sintered bauxite proppants will be used as a baseline for comparison with a range of other particles used for various applications. These results will be made available during the project to the research community to provide updated guidance and inputs to current modeling efforts to improve their results.
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    Numerical Analyses of High Temperature Dense, Granular Flows Coupled to High Temperature Flow Property Measurements for Solar Thermal Energy Storage Dataset
    (Georgia Institute of Technology, 2020-09-24) Yarrington, Justin D. ; Bagepalli, Malavika V. ; Pathikonda, Gokul ; Schrader, Andrew J. ; Zhang, Zhuomin ; Ranjan, Devesh ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    High temperature particle flow properties necessary to predict granular flow behavior for solar thermal energy storage applications were measured and calculated for Carbobead CP 30/60 up to 800 °C. The measured properties included elastic and shear moduli, particle-particle coefficients of static sliding and rolling friction, and particle-particle coefficients of restitution. Poisson’s ratio was calculated with elastic and shear moduli. The flow properties were used as inputs for a numerical model using the discrete element method to examine granular flows along an inclined plane at high temperature. The flow behavior was strongly influenced by the coefficients of static friction, which impacted the particle residence time, shear effects from the side walls, and particle flow mass flux. An 8.7%, 15.6%, and 8.5% increase and 37.9% decrease in steady state mass flow rate was observed for 200 °C, 400 °C, 600 °C, and 800 °C, respectively, when compared to room temperature simulations. A 52%, 59%, and 33% decrease in the time to reach steady state was observed for 200 °C, 400 °C, and 600 °C, respectively, while a 53% increase in time was observed for 800 °C. A significant delay in the flow development at 800 °C was observed due to significantly higher frictional forces.
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    Measurement of Flow Properties Coupled to Experimental and Numerical Analyses of Dense, Granular Flows for Solar Thermal Energy Storage Dataset
    (Georgia Institute of Technology, 2020-06-02) Bagepalli, Malavika V. ; Yarrington, Justin D. ; Schrader, Andrew J. ; Zhang, Zhuomin ; Ranjan, Devesh ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    Granular flows of sintered bauxite proppants were examined along an inclined plane for solar thermal energy storage applications. Granular flow properties needed to drive numeric granular models were measured for improved numerical model predictions for Carbobead CP 50/140, 40/100, and 30/60 particles. Particle shape and size distributions were determined by coupling optical microscopy to an in-house image processing algorithm. The impulse excitation technique was used to measure elastic and shear moduli, and compute Poisson’s ratio. The coefficient of static sliding friction was measured using the slip-stick method, and the static rolling friction was determined from measured shear on particles positioned between two hot-pressed plates. The coefficient of restitution was measured by dropping particles on a surface and determining the kinetic energy before and after impact with the surface using high resolution particle tracking velocimetry. Particle size did not significantly impact the coefficients of restitution and static rolling friction, however, particle shape distribution resulted in a large variation in measurements. An inclined flow experiment was performed to characterize granular flows of Carbobead CP 30/60 particles using particle image velocimetry. Numerical models of the experiment using discrete element method were generated with the measured mechanical properties as inputs for comparison with experimental results. A constant directional torque rolling friction model best predicted bulk granular flow behavior. Good agreement between the model and experiment was achieved at ambient, steady state conditions, with average velocity differences <10%. item_description: Raw measured data of granular flow properties of sintered bauxite at room temperature
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    Characterization of H2O Transport Through Johnson Space Center Number 1A Lunar Regolith Simulant at Low Pressure for In-situ Resource Utilization - Data File
    (Georgia Institute of Technology, 2021-02-04) Schieber, Garrett L. ; Jones, Brant M. ; Orlando, Thomas M. ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    H2O transport through a packed bed of Johnson Space Center number 1A (JSC-1A) lunar regolith simulant was examined at relevant temperatures and pressures for in-situ resource utilization (ISRU) on the Moon. Experimentation was conducted over a range of pressures from 50 to 2,065 Pa at ~350 K, corresponding to Knudsen numbers of 0.3 < Kn < 11 and relevant towards ISRU technologies. A piecewise function was used to evaluate transition and Knudsen regime flows. The piecewise model utilized a Knudsen number that predicted the transition point between advective and Knudsen flows. A transition Knudsen number of 1.66 ± 0.61 and a tortuosity shape parameter of 0.736 ± 0.13 were determined from non-linear regression, and Knudsen diffusivities of 10.62 cm2·s-1, 10.40 cm2·s-1 and 9.04 cm2·s-1 for packed beds of JSC-1A with porosities of 0.388, 0.385, and 0.365, respectively. The experimental measurements, methodology, and modeling provide useful information for ISRU technologies involving the transport of volatiles (e.g., thermal extraction of H2O).
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    Experimental characterization of extreme temperature granular flows for solar thermal energy transport and storage - supplementary data
    (Georgia Institute of Technology, 2022) Bagepallii, Malavika V. ; Jeong, Shin Young ; Brooks, Joshua ; Zhang, Zhuomin ; Ranjan, Devesh ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    High-temperature, dense granular flows along an inclined plane were considered for solar thermal energy transport and storage with sintered bauxite particles. A series of experiments was performed for particle inlet temperatures of ~ 200, 400, 600, and 800 °C to understand the mechanisms of granular flows at extreme temperatures. Mass flow rates were measured using a load cell and free-surface velocities were measured and computed using particle image velocimetry. Surface temperatures were measured using infrared cameras. A significant decrease in steady-state particle mass flow rate was observed with increasing temperature due to changing flow properties. A decrease in bulk particle free-surface velocities was observed at higher temperatures. Free-surface velocity measurement error between experiments were within 20% of the average. The particle surface temperatures decreased from inlet to outlet with larger gradients at higher temperatures observed due to increasing convection and radiative heat losses. A decrease in temperature was observed along the side walls due to a decrease in particle velocities.
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    Temperature Programmed Desorption Comparison of Lunar Regolith to Lunar Regolith Simulants LMS-1 and LHS-1 - Data Files
    (Georgia Institute of Technology, 2022) Clendenen, Ashley Rebekah ; Aleksandrov, Aleksandr ; Jones, Brant M. ; Loutzenhiser, Peter G. ; Britt, Daniel T. ; Orlando, Thomas M. ; School of Chemistry and Biochemistry ; College of Sciences
    Water and molecular hydrogen evolution from Apollo sample 14163 and lunar regolith simulants LMS-1 and LHS-1 were examined using Temperature Programmed Desorption (TPD) in ultra-high vacuum. LMS-1, LHS-1, and Apollo 14163 released water upon heating, whereas only the Apollo sample directly released measurable quantities of molecular hydrogen. The resulting H2O and H2 TPD curves were fit using a model which considers desorption at the vacuum grain interface, transport in the void space between grain-grain boundaries, molecule formation via recombination reactions and sub-surface diffusion. The model yielded a most probable H2O formation and desorption effective activation energy of ~150 kJ mol-1 for all samples. The probability distribution widths were ~100 - 400, ~100 - 350, and ~100 - 300 kJ mol-1 for LMS-1, LHS-1, and Apollo 14163, respectively. In addition to having the narrowest energy distribution width, the Apollo sample released the least amount to water (103 ppm) relative to LMS-1 (176 ppm) and LHS-1 (195 ppm). Since essentially no molecular hydrogen was observed from the simulants, the results indicate that LMS-1 and LHS-1 display water surface binding and transport interactions similar to actual regolith but not the desorption chemistry associated with the implanted hydrogen from the solar wind. Overall, these terrestrial surrogates are useful for understanding the surface and interface interactions of lunar regolith grains, which are largely dominated by the terminal hydroxyl sites under both solar wind bombardment and terrestrial preparation conditions.
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    Advection Diffusion Model for Gas Transport Within a Packed Bed of JSC-1A Regolith Simulant - Data File
    (Georgia Institute of Technology, 2020) Schieber, Garrett L. ; Jones, Brant M. ; Orlando, Thomas M. ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    The advection diffusion model was evaluated for gas transport within a packed bed of lunar JSC-1A regolith simulant at low to medium total pressures over three flow regimes: (1) the slip flow regime (2) the transition regime and (3) the Knudsen regime. These regimes are pertinent to the design of H2O extraction devices for in-situ resource utilization, sampling missions, and surface science. Experimentation was conducted over a range of average pressures of 100 to 25,000 Pa, corresponding to Knudsen numbers between 0.01 and 100 at ambient temperature with Ar and N2. Non-condensing, gases with ideal behavior were evaluated to isolate key flow properties as first step towards evaluating more complex H2O flows. Experimental results were coupled to physical models, and key properties were evaluated to assess the model fit. The experimental results in the transition regime followed the expected behavior based on similar works for microchannel flow and showed that advection is not negligible for transition regime flows. The advection diffusion model in the transition regime fit the results for Knudsen numbers less than unity, and showed the need to further develop gas slip models for Knudsen numbers greater than unity. Key parameters necessary to define were the porosity, tortuosity, pore diameter of the regolith medium, and the gas slip parameter was key in determining the gas-specific transport rate.
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    Characterization of H2O vapor transport through Lunar Mare and Lunar Highland simulants at low pressures for in-situ resource utilization - Data Files
    (Georgia Institute of Technology, 2023) Farr, Tyler P. ; Jones, Brant M. ; Orlando, Thomas M. ; Loutzenhiser, Peter G. ; George W. Woodruff School of Mechanical Engineering ; College of Engineering
    H2O(v) transport through packed beds of Lunar Mare and Lunar Highland simulants was examined for relevant in-situ resource utilization conditions to inform volatile H2O extraction from the lunar surface. Experiments were conducted with different packed beds at average bed pressures of 105 and 3,960 Pa at ~350K for different flow regimes in the range of 0.47 < < 20.7. A piecewise model was used to describe the transition between the advective flow regime to the Knudsen flow regime. Non-linear regression was used to determine a tortuosity shape factor of 2.6175 ± 0.0092 and 0.0937 ± 0.0008, a transition Knudsen number of 1.5984 and 4.0995, and a viscous flow permeability of 0.8238 ± 0.0010 × 10-12 m2 and 5.4805 ± 0.0061 × 10-12 m2 for the Lunar Mare simulant and Lunar Highland simulant, respectively. The resulting Knudsen diffusivities are 6.6530 ± 0.0018 cm2·s-1 and 18.9008 ± 0.0100 cm2·s-1, respectively. These results are necessary for informing the development of in-situ resource utilization technologies for the thermal extraction of H2O.