journal bearings and Raimondi-Boyd charts

journal bearings and Raimondi-Boyd charts
	Post Reply		Engineering Forum

Posted by: aaatai ^®

04/23/2009, 03:04:31

Author Profile
eMail author
Edit

Hi. I have a couple of questions regarding the stuff mentioned on journal bearings and Raimondi-Boyd charts in design textbooks such as Shigley. These charts have been obtained based on the steady state behavior of the bearing (stable lubrication). But when I check the results of some examples in the book or solve some problems based on these charts, the result violates the condition for stable lubrication given by McKee brothers (Mu.N/P > some critical value). Is the given number for this critical value in the book wrong? Second, in the chart for lubricant flow-rate, (Q/rcNl vs. Summerfeld no.), why is it that for infinitely long bearing the flow rate increases with increase in Summerfeld no. while it decreases for small values of l/d ratios? Most charts have the curves for l/d=1/4, 1/2, 1, and infinity. For the first three ratios, the flow rate is decreasing. I have seen a curve for l/d=2 in one book for which the flow rate increases and then decreases. How can it be justified? Thanks

Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post

| |