Potential flow in engine valves Page: 18 of 29
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N. A. C.A. Technical Memorandum No. 343
m = constant, a line is drawn parallel to the a axis. This
line intersects-the curve -at points, each of which determines
two values K and a. These points are now introduced into the
h diagrams and thus the course of the valve lift is plotted
against a. Hence the result is the same here as in the case
treated in Sectton I. We obtain, for constant overlapping., a
diagram of a set of three values of a, K and h. From the h
curves, it is obvious that they run very closely in proportion
wi-th a and K.
The angles of deflection a of the flow is very small in
both IIa and IIb. The m diagrams exhibit, for the customary
overlappings, values up to a equals about 100. All the remain-
ing problems with regard to the different kinds of flow can be
solved with the aid of the computed curves. A knowledge of the
aistance EE' is also important for the flow IIb. This dis-
tance must be determined again by integration. The following
modification of EE' occurs with the valve lift. EE' = m for
n = 0; EE' decreases, as h increases, reaches a minimum and
then increases again. It is easy to determine that, from the
minimum on, there is a flow against pressure. The fact is
mathematically important that the variability of EE' demon-
strates that a flow, in which EE' is obtained by construction,
does not necessarily exist.
4. Distinguishing between the two kinds of flow.- After
the three flows have been successfully calculated from all aides,
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Eck, Bruno. Potential flow in engine valves, report, December 1, 1925; (digital.library.unt.edu/ark:/67531/metadc65148/m1/18/: accessed March 29, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.