The Museum of HP Calculators
The Museum of HP Calculators
This program is by Tizedes Csaba and is used here by permission.
This program is supplied without representation or warranty of any kind. Tizedes Csaba and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.
This program is an example for 'Iteration - General Method' program. This program can calculate friction coefficient in pipes.
For the first (estimated) value of coefficient use Blasius formula, and for iteration use Colebrook formula.
The Blasius formula:
lambda=0.32/(Re)^(1/4)
The Colebrook formula:
1/(SQRT(lambda))=-2*LOG(2.51/(Re*SQRT(lambda))+k/(3.72*d))
and it's iterable form is:
lambda[i]=1/(4*(LOG(2.51/(Re*SQRT(lambda[i-1]))+k/(3.72*d)))^2)
Where lambda[1]: friction coefficient, Re[1]: Reynold's number, k[mm]: roughness
of pipe's wall, d[mm]: inner diameter of pipe
The precision is incredible if you use bigger number at step_39 of program.
Registers: R0: Re-number R1: k/d, relative roughness R2: lambda[i] ### Important: If you want to use this program in pipe-design, check, what is the limit of usage the used formulas (Re-number intervals). And for safety, check the precision of calculated friction coefficient!
00- 01- 45 0 RCL 0 02- 4 4 03- 15 1/x 04- 14 y^x 05- 15 1/x 06- 48 # 07- 3 # .32 08- 2 # 09- 20 mul 10- 44 2 STO 2 11- 11 sqrt 12- 45 0 RCL 0 13- 20 mul 14- 15 1/x 15- 2 # 16- 48 # 2.51 17- 5 # 18- 1 # 19- 20 mul 20- 45 1 RCL 1 21- 3 # 22- 48 # 3.72 23- 7 # 24- 2 # 25- 10 div 26- 40 add 27- 42 13 LOG 28- 42 11 sq 29- 4 4 30- 20 mul 31- 15 1/x 32- 36 ENTER 33- 36 ENTER 34- 45 2 RCL 2 35- 30 sub 36- 42 11 sq 37- 11 sqrt 38- 26 EEX 39- 4 4 40- 16 CHS 41- 34 x change y 42- 42 10 x<=y? 43- 22 47 GTO 47 44- 33 roll down 45- 33 roll down 46- 22 10 GTO 10 47- 33 roll down 48- 33 roll down 49- 31 R/S 50- 22 00 51- 22 00 (P-51 r-04)
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