LAB 1 MEC516

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Toronto Metropolitan University *

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516

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Mechanical Engineering

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Oct 30, 2023

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Department of Mechanical and Industrial Engineering Please select your current program below: ● Mechanical Engineering Industrial Engineering Course Number 516 Course Title MEC Semester/Year 5 th SEM 3 rd YEAR Section Number 06 Group Number 1 Assignment No. 1 Assignment Title Measurement of Dynamic Viscosity Submission Date September 18th 2023 Due Date September 18th 2023 Student Name Student ID (xxxx1234) Signature * James Mohrhardt Xxxx97151 (Note: Remove the first 4 digits from your student ID) *By signing above you attest that you have contributed to this submission and confirm that all work you have contributed to this submission is your own work. Any suspicion of copying or plagiarism in this work will result in an investigation of Academic Misconduct and may result in a “0” on the work, an “F” in the course, or possibly more severe penalties, as well as a Disciplinary Notice on your academic record under the Student Code of Academic Conduct, which can be found online at: http://www.ryerson.ca/senate/policies/pol60.pdf .

Lab Questions: 1a) Use Equation (6) to calculate the dynamic viscosity (in N∙s/m2) using the data for each falling sphere. For each sphere size, check that the low Reynolds number criterion (Equation (7)) is met. Include one sample calculation for one sphere size in your report. Present your results in tabular form listing sphere size, calculated Re and calculated viscosity. Sphere Diameter Mass Time to fall 20 cm at terminal velocity (s) small 6.35 0.15 17.5 Medium 9.51 0.50 9.1 Large 12.25 1.07 5.1 Table 1: Experimental data Sphere size Calculated Re Calculated dynamic viscosity Small 0.146 0.442 Medium 0.377 0.494 Large 0.862 0.496 From the information gathered from the table above we can clearly see that the calculated Re does satisfy the requirement of being under 1 in all three cases.

1b) The viscometer reading for the oil used above is shown in the picture below. How do your results compare to this reading? What are some possible explanations for any discrepancies (if there are any)? As shown from the calculations done from the experimental data, we have a large range from smallest sphere which was 10.9 percent all the way to 22.4 percent. Compared to this reading we can clearly see that the small sphere is the closest to the BYK-Brookfield DVE rotational viscometer measurement and the largest being the farthest away by inspection. Some room for error here could have been how the values were gotten from the timer used back in the falling sphere experiment which could have introduced human error since reaction times are way slower then a sensor or another method of stop starting time. 2) Viscosity measurements were made at two different spindle speeds (12 rpm and 6 rpm) with the rotational viscometer. Within the accuracy of the instrument, these two viscosity measurements were the same. Why? What does this tell you about the gear oil? (Hint: For what broad classification of fluids would you expect the viscosity to depend on shaft rotational speed?) The velocities measured at the two different speeds were the same because the rotational viscometer was measuring the viscosity of a Newtonian fluid was the gear oil in this specific scenario. This tells us that if the experiment was conducted on a non-Newtonian fluid, it would cause a change in the viscosity with different spindle speeds due to the shear rate. As we know if the shear rate increases with that the viscosity will greatly decrease and vice versa. 3) Compare your falling sphere results to the measurements from the rotational viscometer. Which size of sphere produced the most accurate result? Why? Comparing the results together it is clear that the small sphere was found to have the most accurate results out of the other two. It had a low Reynolds number which means stokes law was close to accurate. As shown in the previous question giving us a percent of 10.9 off.

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4) Compare your viscosity measurements with the manufacturer’s specifications from the internet. Is this data consistent with your measurements? If a conversion is needed, show this in the sample calculations. When making this comparison, be sure to discuss the effect of temperature on the oil’s viscosity. (A direct comparison at room temperature may not be available.) Temperature (°C) Calculated Dynamic Viscosity (kg/ms) -26 112 40 0.129 100 0.013 Table 3: The data gotten from the table is somewhat consistent with the measurements because this specific experiment was done at room temperature so there will be some offsetting numbers since its not the exact same. When comparing it to the dynamic viscosity at 40 degrees it should be at least double what it currently is right now (0.258kg/ms). From the experimental data which was received it should really be about 3 times more being compared to manufacturers specifications for Quaker State SAE 80W-90 GL-5 . There isn’t a set number to ref er to but overall, these numbers are semi consistent with what should be observed. 5) Viscosity is a very important property for many products and industrial processes. Can you list three products where proper viscosity is important and discuss why? Are these products Newtonian? As an example, consider ketchup, a non-Newtonian fluid. Manufacturers try to ensure that the viscosity of their ketchup falls in a narrow range so that consumers get a consistent product that flows at reasonable rates. If one batch has an unusually low viscosity, consumers might flood their burgers with it. Conversely, a batch with unusually high viscosity may not flow out of the bottle, frustrating the consumer. Three products that proper viscosity is important are honey, paint, and petroleum. Honey is a purely viscous Newtonian fluid, used by many on a day-to-day basis. Manufacturers make sure to have the easy bottled honey at users disposal to pir out from a sma ll nozzle and create airtight seals, so it doesn’t harden back to the original form (hard and non viscous). This would result in the consumer being frustrated from not being able to get the honey out of the bottle. On the opposite side of things with constant seal of the nozzle it should prevent from hardening and let it flow easily without effort. Secondly, we have paint, while having some Newtonian and some non-Newtonian paints it really depends on what type of look your going for due to there being a variety of types to choose from. Thinner paints are usually used to be sprayed and applied to large surface areas with ease and short dry time periods while the thicker clumpier viscous paints are usually used on rollers and take the shape or texture of the roller giving it a different finish. Increasing dry time but still does the same application as user desires.

Lastly, we have petroleum, the crude oil is considered a non-Newtonian fluid but at low temperatures but does still have some properties as its cooled down as a Newtonian fluid. The low viscosity oils are usually used to reduce friction in engines and help engines start up quickly and most efficient as possible especially during the colder weathers. On the opposite side of things, the high viscosity oils are mainly used to act as a film and protect engines at high temperatures.

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