1、NASA TN D-6453 NASA TECHNICAL NOTE M Ln * 7 n z c $4 Wi 4 FILE. COPY z FORTRAN PROGRAMS OF LIQUID-TO-LIQUID FOR THE DESIGN JET PUMPS L by Nelson L. Sungsr Lewis Reseurch Center Cleveland, Ohio #I39 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. JULY 1971 Provided by IHSNot for Resal
2、eNo reproduction or networking permitted without license from IHS-,-,-1. Report No. NASA TN D-6453 FORTRAN PROGRAMS FOR THE DESIGN OF LIQUID-TO- LIQUID JET PUMPS 2. Government Accession No. 3. Recipients Catalog No. 4. Title and Subtitle Lewis Research Center National Aeronautics and Space Administr
3、ation 5. Report Date 11. Contract or Grant No. 7. Author(s) Nelson L. Sanger 9. Performing Organization Name and Address 8. Performing Organization Report No. E -6089 10. Work Unit No. 128-31 I 5. Supplementary Notes Cleveland, Ohio 441 35 12. Sponsoring Agency Name and Address National Aeronautics
4、and Space Administration Washington, I). C. 20546 6. Abstract The one-dimensional equations describing noncavitating and cavitating flow in liquid-to-liquid jet pumps were programmed for computer use. Each of five programs was written to incor- porate a different set of design input conditions. The
5、programs may be used for any liquid for which the physical properties are known. Calculations for noncavitating and cavitating performance were combined, permitting calculation of cavitation limits within the program. Design charts may therefore easily be developed without the manual iteration which
6、 is com- mon to existing design methods. Sample design problems are included to illustrate the use of each program. 13. Type of Report and Period Coyered Technical Note 14. Sponsoring Agency Code 7. Key Words (Suggested by Author(s) Jet pumps Fluid flow Pumps 9. Security Classif. (of this report) Un
7、classified 18. Distribution Statement Unclassified - unlimited 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified 43 $3.00 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-FORTRAN PROGRAMS FOR THE DESIGN OF LIQUID-TO-LIQUID J
8、ET PUMPS by Nelson L. Sanger Lewis Research Center SUMMARY The one-dimensional equations describing noncavitating and cavitating flow in liquid-to-liquid jet pumps were programmed for computer use. Each of five programs were written to incorporate a different set of design input conditions. The prog
9、rams may be used for any liquid for which the physical properties are known. Calculations for noncavitating and cavitating performance were combined, permitting calculation of cavitation limits within the program. Design charts may therefore easily be developed without the manual iteration which is
10、common to existing design methods. each case, a sample design problem is solved which illustrates the procedures and the types of charts that can be developed. The program inputs consist of pertinent pressure, flow, and geometric variables; estimated friction loss coefficients; and fluid properties.
11、 Outputs consist of the basic jet pump nondimensional parameters; other pertinent pressure, flow, and geometric varia.bles; and an indication of whether the flow is cavitating or noncavitating. gram are less than 1 minute on IBM-7094 equipment. The equations and method of calculation are presented f
12、or each program. And in Listings of the FORTRAN IV programs are included. Execution times for each pro- INTRODUCTION The liquid-to-liquid jet pump has found increasingly wide application in recent years. Some examples of its diverse usage include reactor coolant circulation pumps, aircraft fuel pump
13、s, and condensate boost pumps for Rankine cycle space electric power systems. To keep pace with the renewed interest in jet pumps, analytical and ekperimental re- search of their performance characteristics has also expanded. Attention has been di- rected toward optimization of geometry (refs. 1 and
14、 2), cavitation performance (ref. 3), staged operation (ref. 4), and the operating characteristics of low-area-ratio jet pumps Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-(ref. 5). Analytical and empirical relations have been developed which accu
15、rately predict both noncavitating and cavitating jet pump performance (refs. 3, and 6 to 10). Yet, despite the greater amount of information, the designer of a jet pump for a spe- cific application is still faced with a cumbersome task. Design charts of a general nature are available in some papers,
16、 but are restricted to noncavitating operation and to a rela- tively narrow range of area ratios. Separate calculations are necessary to check for cav- itation limits. And, in most cases, several manual iterations are necessary. To simplify and reduce the amount of work involved in the design proced
17、ure, the non- cavitating and cavitating procedures have been combined and programmed for computer use. Five design routines are presented in this report. Each of them corresponds to a commonly encountered jet pump design problem. FORTRAN IV listings for each are in- cluded. The program can be used f
18、or any liquid for which the physical properties are known. Therefore, for a given set of input conditions, a designer can easily and quickly develop a complete set of predicted performance curves showing the cavitation limits as well as the required physical dimensions. DESIGN EQUATIONS A schematic
19、representation of a jet pump is shown in figure 1, and all symbols used are defined in appendix A. The primary fluid (fig. 1) is pressurized by an independent source and leaves the nozzle as a core of high-velocity fluid. It is separated from the secondary stream by a region of high shear. Turbulent
20、 mixing between the two fluids occurs in this region, which grows in thickness with increasing axial distance from the Diffuser -Throat-t I D CD-9434 Figure 1. - Schematic representation of a jet pump. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-
21、,-nozzle exit. The lowest pressures in the flow field occur in the shear region, and there- fore cavitation inception occurs there also. A ssu m pt io n s The assumptions that are used in the analysis are (1) Both the primary and secondary fluids are incompressible. (2) The temperatures of the prima
22、ry and secondary fluids are equal; therefore the (3) Spacing of the nozzle exit from the throat entrance is zero. (4) Nozzle wall thickness is zero. (5) Mixing is complete at the throat exit. specific weights are equal. Basic Parameters and Design Equations Four basic jet pump parameters, all expres
23、sed in dimensionless form, are used. (1) Nozzle-to-throat area ratio They are n A R=- At (2) Secondary-to-primary flow ratio (3) Head ratio D - 2 N= 1 - D (3) (4) Efficiency q=MN ( 4) 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The noncavitatio
24、n analysis consists of an application of continuity, momentum, and energy equations across the jet pump (see ref. 8 for complete development). Because the anal- ysis is one-dimensional and the mixing process is three-dimensional, the analysis must be supplemented by empirical information to determin
25、e optimum throat lengths, nozzle positions, diffuser geometry, and area ratios for specific applications (e. g. , see “Design Considerations“ section of ref. 5). The formula for head ratio which results from the analysis is RM 22 2 ZR + 2R - (1 + Kt + Kd)R (1 + M) - (1 + Ks) 1 -R N= (1 - R)2 2 2 22
26、P 1 -R l+K -2R- 2R + (1 + Kt + Kd)R (1 + M) The theoretical expression for efficiency is obtained by multiplying equation (5) by M. The formula for primary flow rate W1 is yAngc w1 =- 144g and the formula for primary nozzle 144Wlg A= n gCy J (1 + Kp) - (1 + Ks) exit area An is derived from it: MR Fr
27、iction losses are taken into account through the use of friction loss coefficients K, which are based on dimensionless total-pressure losses in individual components of the pump, such as the primary nozzle, throat, and diffuser. The friction loss coefficients may be determined either by estimating t
28、he values on the basis of information in the lit- erature (refs. 6 to 8) or by calibrating the individual components. Several cavitation prediction parameters have been proposed. One of them aL has been recommended for design use in a summary report on jet pump cavitation (ref. 3). 4 Provided by IHS
29、Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-It was developed independently in 1968 by this author at NASA (referred to as the alternate cavitation parameter cy in ref. 9), and also by Hansen and Na (referred to as a in ref. 10). The parameter predicts condition
30、s at the head-rise breakdown point, which is also the limiting flow point (not incipient cavitation) and is defined as where Vs is the secondary fluid velocity at the throat entrance (fig. l), A value for the minimum secondary inlet pressure required to prevent cavitation can be calculated from equa
31、tion (8), where A, and R enter the relation from equation (1). The criterion used in the com- puter programs to determine cavitation-limited conditions is a comparison of PZREQD and the available P2. The noncavitating theory predicts experimental performance quite well over a wide range of area rati
32、os and flow conditions. Comparisons between theory and experimental performance are presented in references 6 to 8. Cavitation-limited flow conditions have been investigated by various researchers, and empirical values for aL have been established. These values are summarized in reference 3. A conse
33、rvative design value for aL is 1.35. Well-designed secondary in- let regions allow values of CT gram and may be specified by the user. In the numerical examples presented later in this report, a = 1.1 is used. from 1.0 to 1.1 to be used; cr is an input to each pro- 5 Provided by IHSNot for ResaleNo
34、reproduction or networking permitted without license from IHS-,-,-DESIGN PROGRAMS AND PROCEDURES I11 IV v I I1 I11 I I1 Because of the diverse applications possible, there are several combinations of in- put conditions which a designer might encounter. Five combinations are presented in this section
35、 and the theoretical equations are developed into five design programs. The equations for each program are followed by a sample design problem illustrating use of the program. A FORTRAN IV listing of each program is given in appendix B. Execution time for each program is less than 1 minute on IBM-70
36、94 equipment. The choice of which program to use will depend on what input information is avail- able, and what output is desired. Table I summarizes the input-output features of each program. Until the user is familiar with all the programs, table I should be used as a starting eoint. chart develop
37、ment since PI and W2 are the only inputs definitely required. The “varying input variables“ (M, R, and P2 for program I) may be selected at random to permit the effects of variation of each to be investigated. If specific values for each of Program I is one of the more versatile programs. Itlends it
38、self quite well to design IV v TABLE I. - INPUT AND OUTPUT VARIABLES FOR EACH DESIGN PROGRAM Input common to all programs: Kp, Ks, Kt, Kd, 7, p, uL. M M MM RR R R p2 p2 1 Program w2 p1 Output variables I Fixed input variables W1 W1 W1 w1 w1 pD PD pD pD dn dn dn dn 2REQD 2REQD ZREQD 2REQD I I dt I dt
39、 I I Varying input variables I I dt 6 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-the varying independent variables are known (either initially or from the output of another program), program I may be run in a straightforward manner to produce
40、only one set of Program 11 is used when the throat diameter of a pump is known, either as a design constraint, or as part of an existing pump that is to be redesigned. Program 111 is the one program that will most often be used in conjunction with some other program. It is used when a pump must be d
41、esigned to operate quite close to the cavitation limit. Pro- gram III identifies the cavitation-limited pump configurations. With this information the designer can apply a safety margin to the appropriate parameter and recalculate the final design using another program (e. g., program I). Program IV
42、 is used when secondary flow rate W2 and pump pressure rise PD - P2 are known, and when there is some flexibility in the choice of driving pressure PI or flow W1. Finally, program V is used when the jet pump geometry is completely speci- fied and it is desired to know the off-design performance. com
43、puter programs. However, in most cases, it should be possible to create new pro- grams by combining the appropriate design equations. The sample design problems presented after each program do not represent the full range of applicability of each program. For some applications, enough information wi
44、ll be available to permit a straightforward once-through design procedure. In other cases, it will be necessary to create design charts before arriving at a final design. others (programs 111 with I, I with 11, and IV with V). How certain programs are used with each other, or if they are, will also
45、depend on the specific application. The combi- nations used in the sample problems in this report are not suggested as the only possi- bilities open to a designer. As experience is gained using the programs, the potential relations between them will become clearer. Finally, a word about design compr
46、omises. In general, the ideal jet pump design would possess several desirable but mutually unattainable qualities. Large amounts of secondary flow W2 would be pumped by a minimum of primary flow W1. This corre- sponds to a high flow ratio, M = W2/w1. The pressure supplied by an outside sourte PI wou
47、ld be kept low while jet pump pressure rise was maximized (PD - Pz). This corre- sponds to a high head ratio, N = (PD - Pz)/(P1 - PD). Efficiency would be high (q = MN), and operation would be cavitation free. goals concurrently would violate the laws of conservation of energy and momentum. Some of
48、the compromises encountered in practice are illustrated in the sample problems. output. Some design problems will probably occur which were not anticipated by these five Similarly, in the sample problems some programs are used in conjunction with In practice, of course, compromises must be made. Ach
49、ieving all these idealized 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Program I Variables. - The known and unknown variables incorporated in program I are as fol- lows: The known variables are (1) Primary fluid inlet pressure P1 (2) Secondary flow rate W2 (3) Flu
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