Quantity [Unit]

Symbol

Nozzle

Nozzle Pressure Ratio NPR (P_o/P_b)

5.0

4.5

4.0

3.67

3.5

Absolute (Stagnation) pressure [MPa]

P_o

Circular

0.505

0.455

0.404

0.371

0.354

Square

0.510

0.459

0.408

0.374

0.357

Gauge pressure [MPa]

P_G

Circular

0.404

0.354

0.303

0.270

0.253

Square

0.408

0.357

0.306

0.272

0.255

Jet pressure ratio (JPR)

P_e/P_b

Circular

1.36

1.23

1.09

1.0

0.95

Square

Exit pressure [MPa]

P_e

Circular

0.138

0.124

0.110

0.101

0.096

Square

0.139

0.125

0.111

0.102

0.097

Fully expanded jet Mach number

M_j

Circular

1.709

1.638

1.559

1.5

1.467

Square

Fully expanded jet diameter / height [μm]

D_j

Circular

1070

1044

1018

1000

991

h_j

Square

Reynolds number

Re

Circular

29875

29083

28140

27410

26991

Square

29978

29182

28237

27504

27084

Operating condition

-

Circular

/ Square

Underexpanded

Full

expanded

Over expanded