Integrated Fluids and Electronics Labs to Measure Fluid Flow

Knowledge of theory is deepened by examining how the theory models the physical world. Exercises in the laboratory can enhance the understanding of the models by demonstrating both the accuracy and the shortcomings of the theoretical models. To help students achieve a better sense of connections between theory and the physical world, we have developed laboratory experiences to measure the flow of fluid using transducers and computer-based instrumentation. The goals of these experiments are to extend students’ knowledge of fluid behavior as well as extend understanding of instrumentation systems. Several experiments were developed and implemented at a very low cost primarily using materials readily available at most hardware stores. In the study of fluid flow behavior, the first lab examines water flow while a second lab looks at air as a fluid. In the first lab, students calibrate a flow meter by manually measuring the mass discharged during defined time intervals. Students use multiple flow rate measurements to ensure a linear response from the meter. The second lab uses air and the students are asked to determine how the calibration for the water flow rate compares to the air flow rate calibration. At this point students demonstrate that the linear velocity of the fluid that is the critical component. Manual verification of the air flow rate measurement is done using a Pitot tube attached to a water filled manometer. Use of the Pitot tube gives students additional experience with the Bernoulli Equation and this important device often used to measure airspeed. The flow meter uses a magnetic turbine and a Hall Effect sensor to generate pulses for each rotation of the turbine. The pulses are read using the counter on the National Instruments MyDAQ and LabVIEW. The students are introduced to the NI MyDAQ in the electric circuit class and associated lab. Students are then instructed on how to build a LabVIEWTM program to read and convert the rotation rate to a linear velocity as well as a volumetric flow rate. This method of integrating theory from different engineering theory courses by engaging students in practical applications helps the students to further their knowledge and understanding in both targeted areas. We are working on new experiences to integrate additional topics.