University of Minnesota
University of Minnesota: Department of Mechanical Engineering
http://www.me.umn.edu/

ME 4331: Fin II

Fin Heat Transfer; Fins Part II

Objective:

The objective of Part II of the fin lab is to expose the student to the "open-ended" nature of design in an experimental setting. The lab teams are expected to address the objective using the 2n-factorial method described in lecture.

The objective is defined by the following problem posed by your employer, who is a small manufacturing firm in northern Minnesota:

Preliminary tests on a new go-cart engine indicate that the head is overheating during operation of the vehicle in the velocity range of 25 to 60 mph. Estimates suggest that the head must dissipate 150 W in steady-state operation over this entire velocity range. You are asked to design a fin array from 6061-T6 alloyed aluminum that can be added to the head assembly to reduce the temperature of the head. Due to space limitations, the overall base dimensions of the fin array are fixed, and can be assumed to be represented by the exposed area of the aluminum heating block in the laboratory. Your first task as a test engineer is to determine the relative importance of the three parameters which you believe will have the largest impact on head temperature, namely: (1) wind approach velocity; (2) fin thickness; and (3) spacing between fins. Furthermore, you determine that the acceptable range for fin thickness and spacing is from 3.18 mm to 6.35 mm (1/8 inch to 1/4 inch). Provide your recommendations on fin design using a 2n-factorial method.

Procedure

You are a highly paid engineer now, so you are allowed to define this yourself.

Reporting Results

The report that you provide to your employer will be of a "informal" nature. In addition to requirements explicitly described in the "Informal Reporting" handout, and as needed to meet the objectives above, you should include the following:

  1. Outline the 2n-factorial method using the (-+) scheme described in lecture, setting up the appropriate tables. One of the tables must compute the EFFECTS to address the stated objectives. The statistical relevance of the EFFECTS must be identified.
  2. In addition to the consideration of head temperature, you are asked to evaluate the following output quantities over the parametric space under consideration:
    • The overall convective heat transfer coefficient.
    • The fin efficiency.
    • The overall efficiency of the fin array.

    (The latter two have been defined in the lecture.)