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Sensor-based Experimental Evaluation of Mixing Characteristics in Laboratory-scale Reactor Systems

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2014 ASEE Annual Conference & Exposition


Indianapolis, Indiana

Publication Date

June 15, 2014

Start Date

June 15, 2014

End Date

June 18, 2014



Conference Session

Laboratory Experiences with Mechanical, Materials and Fluid Systems

Tagged Division

Division Experimentation & Lab-Oriented Studies

Page Count


Page Numbers

24.1078.1 - 24.1078.12



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Paper Authors


Steven C. Chiesa P.E. Santa Clara University

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Professor Chiesa is an associate professor in the department of civil engineering at Santa Clara University. He has been teaching environmental engineering courses at the university level for over 30 years. He holds a B.S. degree from Santa Clara University, an M.S. degree from Stanford University, and a Ph.D. degree from the University of Notre Dame.

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Sensor-based Experimental Evaluation of Mixing Characteristics in Laboratory-scale Reactor SystemsA hands-on laboratory experiment was designed and implemented to evaluate the ability of asensor-responsive dye tracer to characterize the mixing conditions in laboratory-scale reactorsystems. The sensor and its integrated data acquisition and analysis system were chosen toprovide a continuous data track and reduce the need for more traditional wet-chemistry-basedtechniques for data collection. System development required adapting the Turner DesignsCyclops™ Rhodamine-specific sensor for use at lab scale. The experiment required smallstudent groups to configure system components according to a schematic diagram, establish anddocument the system’s steady-state system behavior, and then generate a set of data chroniclingthe system’s response to a pulse input of Rhodamine dye tracer. The data were then used tocompare actual and theoretical (ideal) system mixing behaviors.The developed system has the potential for a variety of experiments of different levels ofcomplexity to be conducted with relative ease. Initial experiments with the system have focusedon the responses of a single continuous flow, completely mixed reactor or four equally-sizedcontinuous flow completely mixed reactors in series. Photographs of the sensor systemconfigured within an experimental system are provided on the following page. Dye tracer levelsin system effluents, as measured by the sensor response, were recorded on a personal computerin a format that could be exported into a commercial spreadsheet program for subsequentanalysis. Students were instructed to analyze the data and critically compare actual behaviorwith responses predicted by models developed in lecture for the associated ideal reactor systemswhen subjected to a pulse dye tracer input. The same basic experimental system, with minormodifications could be used to determine the dispersion number for a more ill-defined reactorsystem and/or estimate the amount of dead volume present in a system.While the actual experimentation and data collection were organized as team activities, studentswere required to individually prepare written reports with a fairly specific list of deliverables.These deliverables included answering a series of basic questions related to the underlyingconcepts behind the experimentation, providing an evaluation of the data in the context of thereferenced ideal system behavior, and finally a discussion of potential sources of error and/orreasons behind and observed differences between actual and theoretical behavior.Intended student learning goals for this exercise has focused on ABET-oriented outcomes forconducting experiments, analyzing data, and using modern analytical tools. Assessment ofstudent learning involved preparing a simple metric for evaluating how well students were ableto address the objectives established for the laboratory exercise. The metric was used as the keypart of evaluating student reports. Results gathered so far indicate that the sensor-based dyemeasurement technology and the computer-based data acquisition system have significantlyimproved the quality of the data used for analytical purposes and has allowed students to focusless on error-causing experimental artifacts and more on evaluating the non-ideal (or ideal)mixing conditions that are designed into the experimental systems.Figure 1. In-line Dye Sensor Set-up Figure 2. In-line Dye Sensor Set-up (system view) (detail view)

Chiesa, S. C. (2014, June), Sensor-based Experimental Evaluation of Mixing Characteristics in Laboratory-scale Reactor Systems Paper presented at 2014 ASEE Annual Conference & Exposition, Indianapolis, Indiana. 10.18260/1-2--23011

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