Labreport

Portland State University

EAS 361 Laboratory

Lab Exercise 0

5 October 2004

Gerald Recktenwald

Lab Partners:

Jane Doe

Jill Jones

Lab Performed 29 September 2004 Joe Smith

1 Introduction

A capillary tube viscometer was used to measuring the viscosity of water as a function of temperature. The purpose of the lab is to gain familiarity with this method of viscosity measurement, and to understand the data reduction process necessary to convert measurements to viscosity values.

2 Apparatus

Figure 1 is a schematic of the viscometer used in the test. Water from the upper chamber flows through the capillary tube and is collected in the graduated cylinder. The upper chamber is surrounded with a thermally regulated water bath that is used to control the temperature of the water during the viscosity measurements. A glass thermometer suspended in the upper chamber is used to record the temperature of the sample fluid. A plastic cooking spoon is used to stir the sample fluid so that its temperature is uniform and so that the system more quickly reached steady state after a change in the thermostat stetting. The flow through the capillary tube is turned on or off with a small ball valve near the outlet of the capillary tube.

[pic]

Figure 1 Capillary viscometer used in the measurements. Image from CD-ROM supplied with course textbook [1].

3 Procedure

Each measurement is at a specified temperature. To prepare for a reading, the water bath thermostat is set to a desired temperature and the system is allowed to come to thermal equilibrium. Typically it takes three to four hours for the temperature of the sample fluid to stabilize.

When the system has achieved thermal equilibrium, the empty graduated cylinder is placed near, but not under the outlet of the capillary tube. The stop watch is reset and the valve on the capillary tube is opened. When the sample is flowing freely and with an...