Heindel,
Theodore
Heindel,
Theodore
Email Address
theindel@iastate.edu
Birth Date
Title
University Professor
Academic or Administrative Unit
Organizational Unit
Mechanical Engineering
The Department of Mechanical Engineering at Iowa State University is where innovation thrives and the impossible is made possible. This is where your passion for problem-solving and hands-on learning can make a real difference in our world. Whether you’re helping improve the environment, creating safer automobiles, or advancing medical technologies, and athletic performance, the Department of Mechanical Engineering gives you the tools and talent to blaze your own trail to an amazing career.
Organizational Unit
Department of Chemical and Biological Engineering
The function of the Department of Chemical and Biological Engineering has been to prepare students for the study and application of chemistry in industry. This focus has included preparation for employment in various industries as well as the development, design, and operation of equipment and processes within industry.Through the CBE Department, Iowa State University is nationally recognized for its initiatives in bioinformatics, biomaterials, bioproducts, metabolic/tissue engineering, multiphase computational fluid dynamics, advanced polymeric materials and nanostructured materials.
History
The Department of Chemical Engineering was founded in 1913 under the Department of Physics and Illuminating Engineering. From 1915 to 1931 it was jointly administered by the Divisions of Industrial Science and Engineering, and from 1931 onward it has been under the Division/College of Engineering. In 1928 it merged with Mining Engineering, and from 1973–1979 it merged with Nuclear Engineering. It became Chemical and Biological Engineering in 2005.
Dates of Existence
1913 - present
Historical Names
- Department of Chemical Engineering (1913–1928)
- Department of Chemical and Mining Engineering (1928–1957)
- Department of Chemical Engineering (1957–1973, 1979–2005)
- Department of Chemical and Biological Engineering (2005–present)
- College of Engineering(parent college)
Related Units
About
Profile Link
Publications
Now showing
1 - 10 of 99
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Article
Investigating gas-solid flow hydrodynamics in spouted beds with a draft tube using XCT: The role of tube types, gas velocity, and diameter
2025-02-28
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Xiang, Zhong
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Chen, Xi
,
Heindel, Theodore
,
Mechanical Engineering
This study explores the gas-solid flow hydro dynamics in spouted beds with various types of draft tubes using X X-ray computed tomography (XCT). We investigate the effects of different draft tube types (non non-porous, porous, and open open-sided), gas velocities, and tube diameters on the spouting behavior. XC T allows for the noninvasive, three three-dimensional reconstruction of time - average voidage distribution within the spouted bed beds. Our findings indicate that draft tube types and diameters significantly influence the minimum spouting velocity, voidage distribution, and particle flow patterns. Porous and open open-sided tubes demonstrate unique gas gas-solid flow characteristics, such as impr oved particle circulation and enhanced radial mixing, compared to non non-porous tubes. This study provides critical insights into the mechanisms of spouting jet stability and the optimization of draft tube designs for industrial applications.
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Article
Plume Spreading Due to Floor Conditions of a Plunging Liquid Jet Using Stereographic Backlit Imaging
2024-01-12
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Pillers, Roy A.
,
Heindel, Theodore
,
Mechanical Engineering
Plunging liquid jets are a multiphase flow studied to understand how gas is entrained in a liquid and the resulting mixing capabilities. From existing literature, it has been hypothesized that rising bubbles play a noticeable role in the multiphase hydrodynamics of the plunging liquid jet bubble plume and that separating the rising bubbles from the incoming liquid jet can result in a significant increase in the depth of the bubble plume. This study explores the effects of separating the incoming liquid jet from the rising bubble plume through floor interactions and compression effects due to a finite tank depth. This configuration is found in many natural and industrial systems, but not within published literature. Using existing theoretical models of infinite depth plunging liquid jet systems, which align reasonably well with captured baseline data, two models are developed for when floor interactions are present, one theoretical and one empirical. The models show a correlation between plume spread and floor interaction with the incoming plunging liquid jet bubble plume. Data acquired through stereographic backlit imaging over a range of flow rates show a reasonable agreement with the proposed models.
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Article
Assessing solid particle mixing using X-ray radiographic particle tracking
2023-05-03
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Nadeem, Humair
,
Jamdagni, Prajjwal
,
Subramaniam, Shankar
,
Nere, Nandkishor K.
,
Heindel, Theodore
,
Mechanical Engineering
,
Department of Computer Science
Mixture homogeneity values are obtained from a binary mixture in a vertically bladed mixer utilizing data extracted from a single tagged particle. X-ray radiography was performed to image the mixer vessel during the mixing process, and the location of the tagged particle was tracked throughout. Mixture homogeneity is quantified using a standard deviation-based Location Distribution Mixing Index (LDMI), the Modified Generalized Mixing Mean Mixing Index (MGMMI), and the Gini Index, all adapted to single-particle data. Mixture homogeneity values obtained using these indices were compared to data extracted using X-ray Computed Tomography (CT), which was quantified using a particle scale mixing index. It was observed that the LDMI was superior in determining the magnitude of mixing, whereas the Gini index was more suited to predicting mixing endpoints. Methods presented in this study pave the way for new process analytical technologies that extract in-line mixture homogeneity values using velocimetric methods while removing the necessity of uniquely identifying and discriminating between tagged particles.
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Other
Iowa Climate Statement 2023: It’s Time to Tap Iowa’s Vast Solar Energy Resources
2023
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Osterberg, David
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Takle, Eugene
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Passe, Ulrike
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Al-Kaisi, Mahdi
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Anderson, Craig A.
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Arora, Rajeev
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Birt, Diane
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Cianzio, Silvia
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Cornette, James
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Cruse, Richard
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Davis, Radford
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Dobson, Ian
,
Fleming, Cody
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Gallus, William
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Glatz, Charles
,
Gutowski, William
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Harrington, Thomas C.
,
Heindel, Theodore
,
Hornbuckle, Brian
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Johnson, Benjamin
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Klaas, Erwin E.
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Liebman, Matt
,
Liu, Lu
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Mathison, Margaret
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McCalley, James
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Merrick, Laura C.
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Michael, James
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Moore, Kenneth J.
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Nair, Ajay
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Nilsen-Hamilton, Marit
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Passalacqua, Alberto
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Pease, James
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Peters, Reuben
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Rasmussen, Mark
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Rongerude, Jane
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Roth, James
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Rudolphi, Thomas
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Russell, Ann
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Ryan, Sarah
,
Schwartz
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Schwartz, Christian
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Shelley, Mack
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Simpkins, William W.
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Summerfelt, Robert
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Thompson, Janette
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Wanamaker, Alan
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Wang, Xinwei
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Wormley, Sam
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Wright, Mark Mba
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Zarecor, Kimberly
,
et al.
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Department of the Earth, Atmosphere, and Climate
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Department of Architecture
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Department of Agronomy
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Psychology
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Department of Horticulture
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Department of Food Science and Human Nutrition (CALS)
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Mathematics
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Veterinary Microbiology and Preventive Medicine
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Department of Electrical and Computer Engineering
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Mechanical Engineering
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Department of Chemical and Biological Engineering
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Plant Pathology and Microbiology
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Natural Resource Ecology and Management
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Department of Civil, Construction and Environmental Engineering
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Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology (LAS)
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Leopold Center for Sustainable Agriculture
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Department of Community and Regional Planning
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Center for Food Security and Public Health
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Department of Aerospace Engineering
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Department of Industrial and Manufacturing Systems Engineering
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Political Science
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Statistics (CALS)
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Ames National Laboratory
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Center for Nondestructive Evaluation
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Institute for Physical Research and Technology
2023 was another year in which global and regional temperatures broke multiple records, and distant heat-exacerbated wildfires degraded Iowa’s air quality. Scientists continue to find that warming temperatures in the global atmosphere and ocean, caused largely by greenhouse gases from fossil-fuel combustion, are interconnected and are a root cause of increasing regional weather disasters1. In Iowa, new evidence links a warmer Gulf of Mexico to wetter spring planting conditions and a warmer atmosphere to rapid drying that creates flash drought and intensified storm systems.2,3 Iowa has multiple opportunities to help mitigate these climate changes with technologies that will also stimulate the economy and produce high-paying jobs.
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Article
X-ray computed tomography (XCT) study of jetting in a fluidized bed: Measurement method development and single component fluidization
2024-10-01
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Chen, Xi
,
Zhong, Wenqi
,
Liu, Shuguang
,
Heindel, Theodore
,
Mechanical Engineering
Air injected into a fluidized bed through a perforated plate distributor may form individual jets above the distributor plate, which can have a significant impact on the gas-solid flow and heat/mass transfer in the dense phase region. Therefore, it is important to study the jetting characteristics in a fluidized bed, but the measurement of such jets is extremely challenging because of the opaque dense phase region. In this paper, an X-ray computed tomography (XCT) measurement system was constructed, and three-dimensional reconstruction software based on the cone beam filtered back projection algorithm (FDK) was implemented. A jet recognition and quantification algorithm was also developed and tested. Based on these methods, the influence of the jet velocity (Uj) and bed material size (dp) on the structure and shape of the jets was studied. The results show that when the jet velocity increases, the average jet length (L), jet maximum diameter (D), and jet volume (V) increase, while the average jet half angle (θ) fluctuates around a constant value. Under the same jet velocity (Uj), the average jet length (L), jet maximum diameter (D), and jet volume (V) are inversely proportional to the bed material size (dp), while the average jet half angle (θ) is directly proportional to the bed material size (dp). Finally, a correlation for jet length (L) in a fluidized bed is proposed. This study provides a new characterization method for jetting in a fluidized bed, and offers unique experimental data for CFD model validation in fluidized bed simulations.
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Article
X-Ray Flow Visualization: Techniques and Applications
2023-12-6
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Heindel, Theodore
,
Mechanical Engineering
Multiphase flows, defined as a discrete phase in a continuous fluid phase, are found in many natural, industrial, and consumer flows, from rain fall and avalanches to petroleum processing and fuel combustion to cookie dough mixing and pasta making. Many of these flows have an interior that is hidden from optical flow measurements, and intrusive probes can modify the flows of interest. Noninvasive measurement techniques, like X-ray flow visualization, provide a means to visualize and quantify the flow conditions in areas obstructed to visual access. Additionally, X-rays are unlikely to modify or alter the flow of interest. This paper reviews various X ray flow visualization techniques, including those using X-rays from tube sources, electron guns, and synchrotron sources. X-ray fundamentals are first reviewed. Then, various X ray imaging techniques are highlighted, and applications of those techniques are summarized using several multiphase flow examples. Advantages and disadvantages of each technique are provided and the unique flow features that can be captured with X-ray flow visualization are summarized. As detailed, X-ray flow visualization is a powerful tool for multiphase flow visualization and characterization, particularly when the flow of interest has limited or no optical access.
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Article
Non-invasive particle-scale investigation of the effects of blade speed and particle properties on mixture homogeneity evolution using X-ray CT
2023-04-20
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Nadeem, Humair
,
Jamdagni, Prajjwal
,
Subramaniam, Shankar
,
Nere, Nandkishore K.
,
Heindel, Theodore
,
Mechanical Engineering
,
Department of Computer Science
A binary system of particles was mixed in a vertically bladed mixer and mixture homogeneity was reported using X-ray computed tomography (CT) and a particle-scale mixing index. The effects of particle density, size, and volume fraction, as well as mixer blade speed on mixture homogeneity evolution were investigated. For same sized particles, mixture homogeneity was found to deteriorate with increasing difference in particle densities. However, this could be countered by controlling for percolation, e.g., mixing heavier particles of larger size with smaller/lighter particles to improve mixing. Increasing blade speeds from 10 rpm to 30 rpm, deteriorated mixing, however, further increases from 30 rpm to 60 rpm resulted in improvements, indicating possible flow regime changes at different rotational speeds. Increases in the volume fraction of large/light particles increased the penetration of these particles to the bottom layers due to overall flow changes, which in turn appeared to improve mixing.
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Article
An XCT study on three-dimensional characteristics of a spout-fluid bed
2024-04-02
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Chen, Xi
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Xiang, Zhong
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Zhong, Wenqi
,
Heindel, Theodore
,
Mechanical Engineering
Spout-fluid beds are widely used in the chemical and petrochemical industries for excellent mixing and heat and mass transfer properties. Understanding the behavior of jets in spout-fluid beds is crucial for optimizing these processes. In this paper, we present a novel experimental method for studying the three-dimensional characteristics of jets in spout-fluid beds using X-ray computed tomography. By employing a gas–solid flow parameter measurement system, we propose an accurate experimental fitting method for voxel voidage values, enabling the three-dimensional reconstruction of the time-averaged voidage in the entire flow field of a spout-fluid bed. These data are then used to develop an image processing algorithm for identifying and quantifying gas jets in the flow field, allowing for measures of jet length, volume, and diameter. We further investigate the effects of static bed height, spouting gas velocity, and fluidizing gas flowrate on the three-dimensional characteristics of jets.
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Article
A computational study of a two-fluid atomizing coaxial jet: Validation against experimental back-lit imaging and radiography and the influence of gas velocity and contact line model
2023-06-01
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Vu, Lam
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Machicoane, Nathanaël
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Li, Danyu
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Morgan, Timothy B.
,
Heindel, Theodore
,
Aliseda, Alberto
,
Desjardins, Olivier
,
Mechanical Engineering
Numerical simulations of liquid atomization in a two-fluid coaxial geometry have been performed using a geometric Volume-of-Fluid method. Experimental measurements have been obtained using visible light back-lit imaging and X-ray radiography. Simulations are validated against experiments, using the same geometry and fluid injection rates of air and water, by showing excellent agreement in quantities such as liquid mass distribution in the spray formation region and the liquid jet length statistics and temporal dynamics. At the nozzle exit, the coflowing liquid and gas streams are separated by a cylindrical splitter plate. The liquid is laminar and modeled using a Poiseuille flow while the gas inflow model and the contact line model are varied. For the gas velocity models, the vorticity thickness is shown to have a strong influence on the downstream liquid distribution; the difficulty of its modeling and routes to overcome them are discussed. For the contact line model, pinning the interface to the inner wall of the splitter plate leads to an initial increase in the diameter of the liquid jet just downstream of the nozzle exit. In contrast, pinning to the outer wall of the splitter plate or allowing for a free moving contact line results in a monotonic decrease in the diameter of the liquid jet as the downstream distance is increased, in agreement with the experimental observations and measurements. A sub-grid scale contact line model based on a static contact angle is introduced. The static contact angle is varied in the model, showing that the liquid remains intact longer as the static contact angle is increased.
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Article
A particle scale mixing measurement method using a generalized nearest neighbor mixing index
2023-02
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Nadeem, Humair
,
Subramaniam, Shankar
,
Nere, Nandkishor K.
,
Heindel, Theodore
,
Mechanical Engineering
The dependence of mixing measurement on the sampling method and scale is a major concern in the characterization of the state of homogeneity of solid particle mixtures. A novel “particle neighborhood” based mixing index, called the generalized nearest neighbor (GNN) mixing index, is developed to measure solids mixing at the particle scale. GNN is a statistically robust, grid-independent index and provides reliable particle scale mixture homogeneity values. The GNN index has a further advantage that it can be readily adapted to mixtures of unequal proportions or mixtures containing more than two species. To test the GNN index, X-ray computed tomography (CT) images are obtained to noninvasively extract detailed particle distribution of binary mixtures consisting of different-density particles in the mixing vessel. CT images are acquired at different mixing stages to accurately describe mixture homogeneity evolution during the mixing process. Mixture homogeneity values are quantified using the novel GNN mixing index, and these values are compared with measurements obtained using different mixing indices, including a standard deviation-based mixing index and a grid-independent location-based mixing index. The GNN mixing index is found to be well-suited for reliable mixture homogeneity reporting at the particle scale.