COMPUTATIONAL VALVE ANALYSIS

ALTHOUGH ULTIMATELY PERFORMANCE OF PNEUMATIC VALVES MUST BE DESCRIBED BY UNSTEADY, UNCHOKED SUBSONIC FLOW CONDITIONS, APPROXIMATIONS WITH ARBITRARY ACCURACY CAN BE OBTAINED FROM COMPUTED PERFORMANCE VALUES UNDER A WIDE RANGE OF STEADY FLOW CONDITIONS.EQUATIONS SETUP FOR COMPUTER SOLUTION SOLVED SIMULTANEOUSLY CAN BE USED TO MAKE REPEATED CALCULATIONS OF PERFORMANCE VARIABLES.THE AMOUNT OF WORK IS PROHIBITIVE FOR OTHER THAN COMPUTER CALCULATIONS, BUT OTHERWISE THIS METHOD CAN SIMULATE EXPERIMENTS WITH VARIOUS VALVE OPENINGS AND IS ABLE TO LIMIT THE SCOPE AND TO GUIDE EXPERIMENTATION, AND IS HELPFUL TO DESIGNERS AND USERS.SINCE PERFORMANCE DEPENDS ON THE FLUID AND ON THE BASIC VALVE CONFIGURATION, WHICH MAKES THE VALVE DO WHAT IS REQUIRED, CONSIDERATION IS RESTRICTED TO A FAMILY OF PNEUMATIC VALVES ALL HAVING THE FOLLOWING SAME BASIC ELEMENTS: 1.A MOVING OR FLOW-RESTRICTING PART; 2.AN ORIFICE OR SEAT; 3.A SPRING SYSTEM COUNTER-ACTING THE FLUID FORCES TO OPEN THE VALVE.THIS CONFIGURATION IS COMMON TO A VARIETY OF VALVES.IN THE PAPER ARE CONSIDERED IN MORE DETAIL: 1.THE NON-RETURN DISK VALVE AND 2.THE FLAPPER VALVE.GENERALIZATION OF THE INDICATED PROCEDURE SEEMS PROMISING BUT SUBJECT TO EXPERIMENTAL DETERMINATION OF THE CONSTANTS.(MODIFIED AUTHOR SUMMARY)