Experiment Lab Report - Pressure measurement and calibration, Boyle's law
Assignment
After the laboratory class, each student needs to write an individual 2000-word laboratory report and submit the report before the due date. Reports must be submitted online through vUWS. The total marks for the report is 15. Following are what you need to include in the report.
Note: Completing the tasks listed below does not guarantee pass mark for this report. The report will be assessed according to the writing of the report, the accuracy of the data, the analysis method and the clarity of the discussion.
- Describe the TH2 apparatus and explain the function of each part listed in Table 1.
- After conducting the tests, complete the working table. Reproduce the working table using Microsoft Excel (or other software).
- To comment on the accuracy of the calibration, you need use graphs that are based on the table. All the graphs must be drawn using computer software (for example Microsoft Excel)
In the report, make the comments on the following.
1. Why does the apparatus need to be primed?
2. Comment on why the pressure gauge and pressure sensor need to be calibrated.
3. Comment on the linearity of the output for the two pressure sensors (Needle angle for the Bourdon gauge, and voltage for the semiconductor sensor). You need to use graphs to analyse the accuracy of the two pressure sensors. Describe how these graphs could be used to calculate the indicated pressure from the arbitrary sensor readings.
4. Comment on the accuracy of calibration for the Bourdon gauge and the semiconductor sensor. Compare the accuracies of the two pressure sensors.
5. Suggest methods by which the accuracy of the sensor measurements could be improved.
6. What other method can be used for calibrating pressure gauges and sensors?
7. Comment on what lead to errors in the calibration in this test.
4. Procedure
This equipment has been designed to operate over a range of pressures from 0 kN/m2 to 200 kN/m2. Exceeding a pressure of 200 kN/m2 may damage the pressure sensors. In order to avoid such damage, DO NOT APPLY CONTINUOUS PRESSURE TO THE TOP OF THE PISTON ROD
WHEN THE PRIMING VALUVE IS CLOSED except application of the masses supplied.
a. Calibrate the Bourdon Gauge
Conversion of an arbitrary scale into the engineering units
1. Set the selector switch on the console to "Output".
2. Spin the piston to reduce the effects of friction in the cylinder. With the needles still spinning, record the angle and pressure indicated by the Bourdon gauge needle, and the voltage displayed on the console.
3. Place a ½ kg mass on the piston, and spin the piston. Record the value of the applied mass, the reading of the pressure and the angle indicated by the Bourdon gauge needle, and the voltage displayed on the console.
4. Increase the applied mass in increments of ½ kg. Spin the piston and record the reading of the pressure on the Bourdon Gauge and the needle angle for each increment.
5. Repeat the measurements while decreasing the applied mass in steps of ½ kg. This gives two readings for each applied mass, which may be averaged to reduce the effect of any error in an individual reading.
6. Calculate the applied pressure at each mass increment.
7. Calculate the average needle angle at each pressure increment.
8. Calculate the average sensor output at each pressure increment.
9. Calculate the pressure corresponding to each degree of angle.
10. Calculate the pressure corresponding to each mV voltage.
11. Convert the angles and voltages read from the Bourdon pressure gauge and the console to the pressures and compare them with the applied pressure.
b. Calibrate the semiconductor pressure sensor
1. Remove all the weight from the cylinder.
2. Slowly open the priming valve. Open the valve to its maximum, and check that the damping valve is also fully open. The fluid in the system will now be at approximately atmospheric pressure (it will be slightly higher than the atmospheric due to the height of the fluid in the reservoir, but this is negligible compared to the range of the sensors).
3. Turn the zero control on the console until the display reads zero, to set the first reference point form the sensor calibration.
4. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, then close the priming valve.
5. Place a large mass on the piston, and calculate the corresponding applied pressure.
6. Spin the piston and adjust the SPAN control until the sensor output matches the applied pressure, to set the second reference point for the calibration.
7. Remove the mass from the piston. Take a set of readings from the calibrated semiconductor sensor, by adding masses to the piston in ½ kg increments. Repeat the readings while decreasing the applied mass. This gives two readings for each applied mass, which may be averaged in order to reduce the effect of any error in an individual reading.
Attachment:- Lab.rar