Master of Engineering

(Mechanicl)

Assessment Instructions:

1. Please familiarise yourself with the EIT Academic Honesty and Misconduct Policy, in order to understand your requirements and responsibilities as a student of EIT.
2. Please refer to our Assessment, Moderation and Student Progress Procedure for information relating to extensions. Extension requests should be submitted to your LSO at least 3 days prior to the due date.
3. Assessments submitted via email will not be accepted.
4. Assessments must be submitted through Turn-it-in (unless otherwise stated). Your submission must:
   1. Be a single document (Word or Excel or PDF only)
   2. Include at least 20 words of machine-readable text, and
   3. Not exceed 10MB.
5. You must use the provided assessment cover page available on your Moodle student homepage. Submissions without a cover page will not be accepted.
6. You must correctly title your document/s. For example:

UNIT#_ASSESSMENT#_YOURNAME_DATE

E.g. ME501_Assessment2_SteveMackay_01Aug2019

1. You must reference all content used from other sources including course materials, slides, diagrams, etc. Do not directly copy and paste from course materials or any other resources. Refer to the referencing section of the EIT eLibrary on Moodle for referencing guides.
2. It is your responsibility to check that you have submitted the correct file, as revised submissions are not permitted after the due date and time.

Important note: Failure to adhere to the above may result in academic penalties. Please refer to the unit outline or EIT Policies and Procedures for further information.
 

Please complete your answers on the assessment cover page document available on Moodle.

Clearly label your question numbers (there is no need to copy the full question over). Include all working out.

Question 1: (80 marks)

An electronic component is mounted on a base 60 x 60 mm. The base temperature is 80oC. It is to be cooled with ambient air at 30oC. The heat transfer coefficient can be taken as 15 W/m2 K. Neglect radiative heat transfer.

1. Calculate the maximum heat dissipation possible if no fins are used. (5 marks)
2. 2. Calculate the heat dissipation possible if a single aluminum (k = 240 w/m K) fin 30 mm high is used over the entire area. Note that it is equivalent to keeping a 60 x 60 x 30 mm aluminum block on the hot base. First make correction for length of the fin as it will not be insulated tip. (15 marks)
3. Find what error will be introduced if it is assumed that fin tip is insulated. (10 marks)
4. Now replace the aluminum block with n number of 3 x 3 mm square fins equally spaced. Make an analysis with n = 121, 36 and find the heat dissipation possible for each case and for uninsulated and insulated fin tip conditions.

(5 marks)

1. What is the % under prediction if insulated fin tip condition is used in each case. (5 marks)
2. Calculate the volume fraction of fins to total geometric volume in d). (5 marks)
3. If the same volume fraction is used as in the case of 121 fins, but the fin dimensions are changed to 5 x 5 mm, first calculate the number of fins (rounded up) and then calculate the total heat transfer. (15 marks)

Question 2: (5 marks)

Based on the information in Question 1, answer the following:

As the volume fraction of fins increases from 0 to 1, does the heat dissipation increase monotonically?

Question 3: (5 marks)

Based on the information in Question 1, answer the following:

For the same volume fraction of fins, should one use large number of small cross-sectional area fins or small number of larger cross-sectional area ones?

Question 4: (10 marks)

Create a 10-minute demonstration

Select any one of the questions above. Create and submit a Loom video/MS ppt video with webcam ON (showing your face) and screen capture showing how you solved the problem and plotted the results using IHT software or MS Excel or any other heat transfer software. The video length should NOT be more than 10 minutes. So, practice well before recording.

Important: This video is one of the mandatory requirements and if you don’t submit this video,

your assessment marks will be zero.

The guidelines on how to create a Loom video: https://www.loom.com/share/159e007948ce4cb8acfee8a99615f388

The requirements are as follows:

• Select any one of the above questions in this assessment.
• Create a Loom Video or MS ppt video: (a) Introduce yourself (b) Demonstrate how you solved the problem using the software.
• Paste the link of your recording within your assessment report.