Course: ENGR 329 Section: 001 Date: 02/26/2010 Instructor: Dr. Jim M. Henry

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1 1 University of Tennessee at Chattanooga Filter Wash Stations, Both Valves Closed Steady State Operating Curve Engineering 329 By Timmy Collins Lilac Team Tim Garner, Walt Mandrel and You Gao Course: ENGR 329 Section: 001 Date: 02/26/2010 Instructor: Dr. Jim M. Henry

2 2 Introduction This experiment is the filter wash station with both valves closed. Using different frequencies for a sine function students will experimentally observe the time response, amplitude ratio and phase shift of the output function of the filter wash system. The report will be divided into seven sections. These sections are Background and Theory, Procedure, Results, Discussion, Conclusion and Appendices. The Background and Theory section will come first and will explain the operation and intended purpose of the filter wash station. The procedure will follow and show how the experiment was run. The Results section will be after the procedure and show the raw data and charts. The Discussion will interpret this data and the conclusions will summarize the report and make any observations on the experiment. Last is the appendix, it will contain graphs, tables, references and sample calculations Background and Theory Experiments for the filter wash station are run remotely through the internet. The programming of the run page will allow the user to select either open or closed valves, time duration and power input. Both Valves Closed Figure 1. Schematic diagram of the Filter Station Figure 1 depicts the Publically Owned Treatment Works Filter Wash System. The experiment is the same without the nozzles or the actual filters. In this experiment the valves, MV302 MV302, to filter washing stations 2 & 3 are closed. The flow rate recording controller, FRC 301 on the control panel, sends a signal to

3 3 the flow control actuator, FCZ 301, to start the pump and run at a certain power level. The flow rate transmitter, FT 301, sends the sampled flow rate to the flow rate recording controller. The control valves, MV302 MV302, block the water from the pump so that the water exits only at the filter washing nozzles. Figure 2. Block Diagram for Filter Wash Station Figure 2 is a block diagram showing the input and output of the filter wash station. The percentage of motor power, 0 100%, is the manipulated variable m(t) which means it is controlled by the user. The Filter Wash Pump System refers to the whole system or figure 1. The Output Wash Water Flow is the controlled variable c(t) that is determined by the manipulated variable and the system. In this experiment the output is the water flow measured in pounds of water per minute. The steady state operating curve (SSOC) was found in the previous laboratory. The average output flow rates and motor inputs were plotted to create the SSOC. Figure 4 is the graph of the SSOC for the system at 20% intervals. Figure 3 shows the system is steady state from 20% to 100%, but is inconsistent below 40% motor input power. The normal operating region for the input is 40% to 100% motor input power, and the normal operating region for the output is about 15 to 24 lb/min. The average slope is calculated by the output divided by the input, which is 0.16 lb/min/%.

4 4 Figure 3. Steady State Operating Curve Procedure The Filter Wash System is designed to be run remotely. For this experiment the motor power percent, time, and flow rate output were recorded. Labview was used to control the system, collect data, and analyze the data. The computers have data acquisition boards installed, and Labview uses these to run and collect data. The program provides output to equipment and data files. The computer operator and the equipment transmitters provide input to the program. Figure 4 shows the flow of information using Labview. Figure 4. Labview information flow

5 5 The experiment can be started by navigating through the internet to the web address: Wash Sine.HTML. Once there the user will need to input the following information: name, address, the baseline input value in percent, the amplitude of the sine wave in percent, the frequency of the sine wave in hertz, the length of the experiment in seconds, and whether or not the control valves, MV302 MV303, need to be closed or open. For this experiment both valves will be closed. Then the user must click the button Run Experiment to start the experiment. During the experiment the Lab View will record the data being collected, which can be exported to Microsoft Excel. From excel graphs and tables can be generated. The baseline input should be approximately the middle of the normal operating range of the input function. The amplitude for the input should be a value that is sufficiently large enough to for the peaks and valleys of the sine wave to be at the limits of the normal operating range of the input function. The experiment should have at least ten different frequencies. Start with the equation ω=1/τ where f= ω/2π. Use half the frequency of the previous frequency each time until the output response is nearly in phase with the input. Then double the starting frequency and each frequency after that until the frequency appears to have no perceptible oscillation. The length of the experiment should be long enough that there is to have at least one complete sine wave with no transients. The following explain what the symbols are on the graph: ΔC=Change in Output ΔM=Change in Input AR=Amplitude Ratio = ΔC/ΔM t=lag time T=Period PA=Phase angle (t/t)x360 ARu = Ultimate Amplitude Ratio KCu = Ultimate Controller Gain f u= Ultimate frequency K=System Gain Figure 4 shows where on the graph the parameters are observed. The violet is the input motor percentage, the red is the output function in lb/min.

6 6 Figure 5. Graph for Sine Input With Frequency of.08 Results Figure 6. Lissajous Graph Frequency = 0.8Hz Figure 6 is the Lissajous graph for a frequency of 0.8 Hz. The motor input power percentage is located on the x axis and the output response in lb/min is located on the y axis.

7 7 Figure 7. Bode Diagrams Figure seven is two Bode diagrams grouped together. The top Bode diagram has the frequency on the x axis vs the amplitude ratio on the y axis. The bottom Bode diagram also has the frequency on the x axis but with the phase angle on the y axis. From the Bode diagrams table one was generated. Table one is a table of results from each motor power input level ran. Input Range K KC u AR u f u Table 1. % Input Results

8 8 Discussion fu 0.6Hz ±0.3 Hz M 15% Amplitude Ratio 0.10 lb/min/% ±0.1 lb/min/% K 0.2 ±0.1 s Ultimate Gain 10.7 lb/min/% ±8.3 lb/min/% Table 2. Final Results Table 2 shows the final results from the experiment with the error using Student s T. These results are averages of three different motor power input percentages. The parameters from the different motor percentages are averages from different frequencies. The ultimate frequency is 0.6 ± 0.3 Hz. The amplitude ratio is 0.10 lb/min/%±0.1 lb/min/%. The gain of the system is 0.2±0.1s. The ultimate gain of the system is 10.7 lb/min/%±8.3 lb/min/%. The error isn t large in magnitude but is significant in percentage. The error in the ultimate frequency and system gain is 50%. The error in the ultimate gain is 78%. The data from table one shows that 70 to 85% motor input is the cause of this error. 55 to 70% and 85 to 100% appear to be close in magnitude. For 70 to 85% the gain, ultimate gain an ultimate frequency are much lower than the other two motor percentages and the amplitude ration is higher. I think that this error could be mitigated by each person interpreting all the graphs then taking an average of those results. Appendix engineering/filter Wash/Filter Wash System Sine.htm The link for the experiment is: engineering/filter Wash/Filter Flow Constant.htm

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10 fu 0.6Hz ±0.3 Hz 10

11 11 M 15% Amplitude Ratio 0.10 lb/min/% ±0.1 lb/min/% K 0.2 ±0.1 s Ultimate Gain 10.7 lb/min/% ±8.3 lb/min/% Input Range K KC u AR u f u

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