Soran University

Faculty of Engineering

Department of Petroleum Engineering

Petroleum Properties

Title: Viscosity of fluids

Experiment No.: 02

Name: Kaify Abubakr

Group: C2

Date: 3 Mar 2019

Supervisor (s): Mr. Foad Yousefi

Mr. Buya Sabri

Ms. Mariam Wanli

Table of Contents
1. Aim .............................................................................................................................. 1

2. Theory ......................................................................................................................... 1

3. Apparatus .................................................................................................................... 2

4. Procedure ..................................................................................................................... 3

5. Calculation .................................................................................................................. 3

6. Results and Discussion ................................................................................................ 4

7. Conclusion................................................................................................................... 5

8. References ................................................................................................................... 6

List of Figures
Figure (1): stand ................................................................................................................... 2
Figure (2): pipette ................................................................................................................ 2
Figure (3): pipette bulb ........................................................................................................ 2
Figure (4): viscometer .......................................................................................................... 2
Figure (5): thermometer ....................................................................................................... 2
Figure (6): heater.................................................................................................................. 2
Figure (7): graph kinematic viscosity vs temperature.......................................................... 5

List of Tables
Table (1): Results ................................................................................................................. 4

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1. Aim
To determine the viscosity of the fluid at various temperature by using a viscometer.

2. Theory
Viscosity is a fundamental characteristic property of all liquids. When a liquid flow, it has
an internal resistance to flow. Viscosity is a measure of this resistance to flow or shear.
Viscosity can also be termed as a drag force and is a measure of the frictional properties of the
fluid. Viscosity is a function of temperature and pressure. Although the viscosities of both
liquids and gases change with temperature and pressure, they affect the viscosity in a different
manner (Viswanath, et al., 2007).

The factors effect on the viscosity:

1. Effect of Temperature: the temperature of the liquid fluid increases its viscosity
decreases. In gases its opposite, the viscosity of the gases fluids increases as the
temperature of the gas increases.
2. Pressure: when increase the pressure on liquids, the viscosity increases because increase
the attraction force between the molecules of liquid.

The kinematic viscosity is the ratio of the dynamic viscosity and the density of a fluid. The
SI unit of the kinematic viscosity is m2/s. Other units are: 1 St (Stoke) = 1 cm2/s = 10−4 m2/s.
1 cSt (centistoke) = 1 mm2/s = 10−6m2/s. Water at 20 °C has a kinematic viscosity of about 1
cSt (ToolBox, 2003).

µ
𝑣=
ρ

Where: µ= dynamitic viscosity (N s/m²)

ρ =density (kg/m³)

v = kinematic viscosity (m²/s)

Dynamic viscosity is the force needed by a fluid to overcome its own internal molecular
friction so that the fluid will flow. In other words, dynamic viscosity is defined as the tangential
force per unit area needed to move the fluid in one horizontal plane with respect to other plane
with a unit velocity while the fluid's molecules maintain a unit distance apart (Viswanath, et
al., 2007).

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 Ostwald viscometer is a commonly used viscometer, which consists of a U-shaped glass
tube held vertically. For more accurate measurements it is held in a controlled temperature
bath. It is also known as a glass capillary viscometer. A liquid is allowed to flow through its
capillary tube between two etched marks and the time of flow of the liquid is measured using
a stopwatch (McKenna, 2003).

3. Apparatus
Martials:

• Water
• Gasoline

Equipment:

• Beaker
• Stand (see Figure (1))
• Pipette (see Figure (2))
• Pipette bulb (see Figure (3))
• Viscometer (see Figure (4))
• Thermometer (see Figure (5))
• Heater (see Figure (6))

Figure (1): stand Figure (2): pipette Figure (3): pipette bulb

Figure (4): viscometer Figure (5): thermometer Figure (6): heater

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4. Procedure
1. Fill the beaker with water.
2. Put the beaker containing water on the heater and heat it to 20 C.
3. Pour the water into the viscometer to a marked line just below the second reservoir.
4. Pull the water to the marked line just above the second reservoir by suction.
5. Allow the water to return to a marked line just below the second reservoir by the
force of gravity.
6. Measure the time that the water had taken passing between two marked lines (the
lines above and below the second reservoir) by using a stopwatch.
7. Fill the beaker with gasoline.
8. Repeat steps above for temperatures 20, 26, 32 and 42 C.

5. Calculation
𝑣 1 𝑚𝑚2
𝑡 = 32.7𝑠 , 𝑐= = = 0.0306
𝑡 32.7 𝑠
𝑔 𝑔
𝑇 = 14 𝐶, 𝑡 = 85.12 𝑠, 𝜌ℎ𝑦𝑑𝑟𝑜 = 0.8280 , 𝜌𝑝𝑦𝑐𝑛𝑜 = 0.8220
𝑐𝑚3 𝑐𝑚3

𝑣 = 𝑐. 𝑡 = 0.0306 ∗ 85.12 = 2.65 𝑚𝑚2/𝑠 = 0.0265 𝑐𝑚2/𝑠

𝜇ℎ𝑦𝑑𝑟𝑜 = 𝜌. 𝑣 = 0.8280 ∗ 0.0265 = 0.0215 𝑝𝑜𝑖𝑠𝑒

𝜇𝑝𝑦𝑐𝑛𝑜 = 𝜌. 𝑣 = 0.8220 ∗ 0.0265 = 0.0213 𝑝𝑜𝑖𝑠𝑒

----------------------------------------------------------------------------------------------------------------

𝑔 𝑔
𝑇 = 20 𝐶, 𝑡 = 86.31 𝑠, 𝜌ℎ𝑦𝑑𝑟𝑜 = 0.822 , 𝜌𝑝𝑦𝑐𝑛𝑜 = 0.8176
𝑐𝑚3 𝑐𝑚3

𝑣 = 𝑐. 𝑡 = 0.0306 ∗ 86.31 = 2.64 𝑚𝑚2/𝑠 = 0.0264 𝑐𝑚2/𝑠

𝜇ℎ𝑦𝑑𝑟𝑜 = 𝜌. 𝑣 = 0.8225 ∗ 0.0264 = 0.0217 𝑝𝑜𝑖𝑠𝑒

𝜇𝑝𝑦𝑐𝑛𝑜 = 𝜌. 𝑣 = 0.8176 ∗ 0.0264 = 0.02158 𝑝𝑜𝑖𝑠𝑒

----------------------------------------------------------------------------------------------------------------

𝑔 𝑔
𝑇 = 26 𝐶, 𝑡 = 88.67 𝑠, 𝜌ℎ𝑦𝑑𝑟𝑜 = 0.8180 , 𝜌𝑝𝑦𝑐𝑛𝑜 = 0.8119
𝑐𝑚3 𝑐𝑚3

𝑣 = 𝑐. 𝑡 = 0.0306 ∗ 88.67 = 2.713 𝑚𝑚2/𝑠 = 0.02713 𝑐𝑚2/𝑠

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𝜇ℎ𝑦𝑑𝑟𝑜 = 𝜌. 𝑣 = 0.8180 ∗ 0.02713 = 0.0222 𝑝𝑜𝑖𝑠𝑒

𝜇𝑝𝑦𝑐𝑛𝑜 = 𝜌. 𝑣 = 0.8119 ∗ 0.02713 = 0.0220 𝑝𝑜𝑖𝑠𝑒

----------------------------------------------------------------------------------------------------------------

𝑔 𝑔
𝑇 = 32 𝐶, 𝑡 = 107.85 𝑠, 𝜌ℎ𝑦𝑑𝑟𝑜 = 0.815 , 𝜌𝑝𝑦𝑐𝑛𝑜 = 0.8095
𝑐𝑚3 𝑐𝑚3

𝑣 = 𝑐. 𝑡 = 0.0306 ∗ 107.85 = 3.3 𝑚𝑚2/𝑠 = 0.033 𝑐𝑚2/𝑠

𝜇ℎ𝑦𝑑𝑟𝑜 = 𝜌. 𝑣 = 0.815 ∗ 0.033 = 0.0269 𝑝𝑜𝑖𝑠𝑒

𝜇𝑝𝑦𝑐𝑛𝑜 = 𝜌. 𝑣 = 0.8095 ∗ 0.033 = 0.0267 𝑝𝑜𝑖𝑠𝑒

----------------------------------------------------------------------------------------------------------------

𝑔 𝑔
𝑇 = 42 𝐶, 𝑡 = 85.7 𝑠, 𝜌ℎ𝑦𝑑𝑟𝑜 = 0.809 , 𝜌𝑝𝑦𝑐𝑛𝑜 = 0.805
𝑐𝑚3 𝑐𝑚3

𝑣 = 𝑐. 𝑡 = 0.0306 ∗ 85.7 = 2.622 𝑚𝑚2/𝑠 = 0.0262 𝑐𝑚2/𝑠

𝜇ℎ𝑦𝑑𝑟𝑜 = 𝜌. 𝑣 = 0.809 ∗ .0262 = 0.021 𝑝𝑜𝑖𝑠𝑒

𝜇𝑝𝑦𝑐𝑛𝑜 = 𝜌. 𝑣 = 0.805 ∗ 0.0262 = 0.020 𝑝𝑜𝑖𝑠𝑒

6. Results and Discussion

Table (1): Results

Temperature (C) v (cm2/s) 𝜇ℎ𝑦𝑑𝑟𝑜 (𝑝𝑜𝑖𝑠𝑒) 𝜇𝑝𝑦𝑐𝑛𝑜 (𝑝𝑜𝑖𝑠𝑒)

14 0.0265 0.0215 0.0213

20 0.0264 0.0217 0.02158

26 0.02713 0.0222 0.0220

32 0.0330 0.0269 0.0267

42 0.0262 0.021 0.020

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 Viscosity of gasoline
0.03

0.025
kinematic viscosity (poise)

0.02

0.015
μ_hydro
μ_pycno
0.01

0.005

0
0 5 10 15 20 25 30 35 40 45
Temperature (C)

Figure (7): graph kinematic viscosity vs temperature

In this lab experiment, viscosities of gasoline were measured at several different
temperatures. The results were not acceptable. However, there will always be some errors. One
of the problems that are worth to be mentioned was that the gasoline was cooled down due to
the repetition of the test several times. Another reason that was arisen during performing the
experiment was that the air in the Oswalt viscometer could not be emptied. This led to errors
in the results. During recording the time from the stopwatch, errors occurred because more than
one person has done the job, and it became a source of error. during the tests releasing the
gasoline may have not been constant. As explained in the theory section temperature and
viscosity are inversely proportional but, in the tests, it seems that they are directly proportional,
meaning the provided data is not perfect.

7. Conclusion
The experiment was run to measure the viscosity of the gasoline at various temperatures.
the results were found not to be acceptable due to the errors happened during the experiment.
unfortunately, the hypothesis for calculating the viscosity using viscometer was not confirmed.

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8. References
• McKenna, B. a. K. D., 2003. Texture in Food: Semi-Solid Foods. s.l.:Woodhead
Publishing.

• ToolBox, E., 2003. Absolute, Dynamic and Kinematic Viscosity. [Online]

Available at: https://www.engineeringtoolbox.com/dynamic-absolute-kinematic-
viscosity-d_412.html
[Accessed 3 Mar 2019].

• Viswanath, D. S. et al., 2007. Viscosity of Liquids. s.l.:Springer.

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