Mark: %
MAIN ASSIGNMENT
DATE: 20 JULY 2020
SUBJECT: MECHANICAL ENGINEERING DESIGN I CODE: MED21A
MAXIMUM MARKS: 50
INSTRUCTIONAL PROGRAMME: DIP.ENG.TECH: MECHANICAL ENGINEERING
N.DIP ENGINEERING: MECHANICAL
ASSESSOR: DR. L. MUGWAGWA
Question: 1 2 3 Total
Allocated marks:
/25 /15 /10 /50
STATIONARY:
Programmable alphanumerical calculators are NOT allowed
Textbook: Mechanical Engineering Design – Peter RN Childs
INSTRUCTIONS:
Answer all questions in this question paper
Show all calculations with the necessary steps
Work written in pencil will not be marked.
No half marks will be allocated
Round off to 3 decimal places
Student to complete this block:
STUDENT NUMBER:
SURNAME AND INITIALS:
(Write in Block Letters)
SIGNATURE OF STUDENT:
(You have read the instructions on this page)
THIS PAPER CONSISTS OF 10 PAGES INCLUDING THIS COVER PAGE.
, Page |2
QUESTION 1: BEARING DESIGN [25]
A full journal bearing has a nominal diameter of 50 mm and bearing length 25 mm. The
bearing supports a load of 1450 N and the journal design speed is 2500 rpm. The radial
clearance is 0.025mm. An SAE 10 oil has been chosen and the lubricant supply temperature
is 50°C. Using the standard Raimondi and Boyd design charts, find the temperature rise of
the lubricant, taking ΔT = 20°C as the initial assumption. (NB: Carry out the necessary
number of iterations) [25]
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MAIN ASSIGNMENT
DATE: 20 JULY 2020
SUBJECT: MECHANICAL ENGINEERING DESIGN I CODE: MED21A
MAXIMUM MARKS: 50
INSTRUCTIONAL PROGRAMME: DIP.ENG.TECH: MECHANICAL ENGINEERING
N.DIP ENGINEERING: MECHANICAL
ASSESSOR: DR. L. MUGWAGWA
Question: 1 2 3 Total
Allocated marks:
/25 /15 /10 /50
STATIONARY:
Programmable alphanumerical calculators are NOT allowed
Textbook: Mechanical Engineering Design – Peter RN Childs
INSTRUCTIONS:
Answer all questions in this question paper
Show all calculations with the necessary steps
Work written in pencil will not be marked.
No half marks will be allocated
Round off to 3 decimal places
Student to complete this block:
STUDENT NUMBER:
SURNAME AND INITIALS:
(Write in Block Letters)
SIGNATURE OF STUDENT:
(You have read the instructions on this page)
THIS PAPER CONSISTS OF 10 PAGES INCLUDING THIS COVER PAGE.
, Page |2
QUESTION 1: BEARING DESIGN [25]
A full journal bearing has a nominal diameter of 50 mm and bearing length 25 mm. The
bearing supports a load of 1450 N and the journal design speed is 2500 rpm. The radial
clearance is 0.025mm. An SAE 10 oil has been chosen and the lubricant supply temperature
is 50°C. Using the standard Raimondi and Boyd design charts, find the temperature rise of
the lubricant, taking ΔT = 20°C as the initial assumption. (NB: Carry out the necessary
number of iterations) [25]
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