This page contains links to the MATLAB codes, Excel spreadsheets, and LabVIEW VIs used in ME 449/549. The class material is provided as a convenience to students enrolled in the class. Anyone visiting this site is welcome to download and use these notes and lab exercises for their own education.
This material is copyright © 2001-2006 Gerald Recktenwald. All rights reserved. These notes may not be reproduced and distributed for profit using any means, or in any form without permission in writing from the author, Gerald Recktenwald.
Use of these materials in courses at other academic institutions can be arranged. Please to let me know that you are using my notes. I would like proper attribution for these materials.
You can save yourself a lot of hassle by downloading the entire toolbox as a single zip archive. In addition to avoiding the tedium of downloading each file individually, this zip archive contains to most up-to-date version of each of the programs.
The following codes support analysis of thermal lab data, but they do not directly involve calculations for temperature, pressure or flow rate.
The flowBench.xls spreadsheet performs data reduction for flow bench measurements. Input data are pressure differences and temperatures. Conversions of raw pressure transducer and thermocouple EMF are not included.
The following codes are described in this PDF document.
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The PX Series of differential pressure transducers have a linearized output. To a good approximation the output can be converted with the following simple relationship
dp - dpmin Vout - Vmin
--------------- = -------------
dpmax - dpmin Vmax - Vmin
where dp is the pressure sensed by the transducer, dpmin and dpmax are the minimum and maximum values of the pressure range for the transducer, Vout is the output voltage, and Vmin and Vmax are the minimum and maxium voltages corresponding to dpmin and dpmax. For the PX series, Vmin=1 V, and Vmax = 5 V.
Using the linearized output, along with Vmin=1 V, and Vmax = 5 V, the preceding equation can be rearranged as
dp = dpmin + 0.25*(dpmax - dpmin)*(Vout - 1)
Therefore, the simple conversion relationship for a PX series transducer with the range 0 to 10 inches of water is
dp = 2.5*(Vout - 1)
where Vout is the voltage output of the transducer and dp is the pressure in inches of water
To squeeze as much accuracy as possible out of the pressure transducer measurement, a least squares line fit was performed on the calibration data supplied with each transducer. These line fit functions are incorporated in the MATLAB codes listed below. The curve fits and the codes are described in this PDF document. Also note that the MATLAB codes take an input voltage and return the pressure in Pascals, not inches of water.
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The following mfiles perform data reduction on manual flow bench measurements. Use of the mfiles is documented in notes handed out in class.
myFanCurve
loads data from a single data file, performs data reduction, and plots
the fan curve. Use this instead of myFanCurves
when you have only one data set, or when you only want to work
with one data set.You can test the preceding mfiles with the following files containing data from fan curve measurements.
The following mfiles perform data reduction on flow bench measurements taken with the DAQ system.
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The following mfiles perform basic post-processing of data collected from the BenchLink software.
NOTE: To run the flowBenchDataSelector
tool you need both the mfile flowBenchDataSelector.m
and the figure file flowBenchDataSelector.fig
in your MATLAB path.
You can test the flowBenchDataSelector tool on the
sampleFlowBenchRaw.dat file.
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