Paul, been reading your book "How to Cool Your Wankel".  Thanks for the
wonderful book.  I was intrigued by the wedge shaped diffuser but I
noticed that you did not include any description of the optimal shape
and dimensions (i.e., Figure 4, value A1 -- area of the diffuser at its
largest).  Is this information in the Kay and London book?

This review of the Kay and London book makes me a little nervous about
spending money on it (www.amazon.com <http://www.amazon.com>):

"
Although the author addresses many of the issues of design there is only
a half-hearted attempt at examples. Kays speaks to the PhD level not the
working engineer. I was hoping for a book more like Kern's "Process Heat
Transfer," or even Bird, Stewart, and Lightfoot's "Transport Phenomena."

*Here's a good example, on page 45, "Procedures for Sizing a Heat
Exchanger." Instead of taking the reader through the bloody details as
Kern would do, the author refers us back to Figure 2-12, a block-flow
diagram giving the reader a vague understanding of the steps involving
sizing an exchanger. In the end, in fact, on the same page, the author
finishes with: " The complete design of a heat exchanger involves a
whole set of considerations, as indicated by Fig. 2-12." This is clearly
a cop-out. *
"
My scenario would have a fixed size airscoop feeding air to the wedge
diffuser so I need to know the optimal value A1 (input size for the
airscoop) for a heat exchanger of a certain size.

Thank you for any help you can provide.

-Alan Cossitt

P.S.  I'm working on cooling system for a Hirth 3701 85hp 2-cycle
engine.  My current cooling system is adequate but I am going to try to
improve the cooling system this winter to get another 50% of so
efficiency and move the cooling system out of adequate to robust.

--------------------------------------------------------------------------
Thanks for the complement.

The bigger the opening the slower the speed at which it will provide
cooling but the higher the drag. Best to use the simple under the
fuselage design and make it adjustable.

Kays & London  is the only comprehensive book on the subject as far as I know.
I'll have to take a look at the books you mentioned.

The institute of Mechanical Engineers London every few years has a conference
on heat exchangers and there are some more practical papers given
at that conference. http://www.imeche.org/ It seems that nobody presents
useful papers to the SAE anymore as the auto biz has become highly competitive.

It is hard to wade through a lot of this stuff as there appears to be no
standard in nomenclature.
-- --
Paul Lamar ...No rotor no motor.

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.