# ASME PTC 2010 - Intergraph Smart Instrumentation - 13.1 - Reference - Hexagon PPM

## Integraph Smart Instrumentation Sizing Equations

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English (United States)
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Intergraph Smart Instrumentation
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Reference
Smart Instrumentation Version
13.1
1. Calculate mounting factor:

*L [m]

• Other connection types:

2. Calculate Reynolds number:

3. Calculate Strouhal number:

4. Calculate natural frequency:

*L [m], B[m,] E[Pag]

1. Calculate average outside diameter:

• Tapered thermowell:

• Other thermowells:

1. Calculate approximate natural frequency:

2. Calculate correction factor Hf

• Tapered and straight thermowell:

• Stepped thermowell:

1. Calculate correction factor Haf:

2. Calculate correction factor Has:

3. Calculate natural frequency with ideal support:

4. Calculate natural frequency of the mounted thermowell:

5. Calculate Vortex shedding frequency

*B[m]

6. Calculate Scruton number:

*B[m]

7. Calculate miscellaneous parameters:

*B[m], L[m], E[Pag

1. Parameter Gsp

• Tapered and straight thermowell:

• Stepped thermowell

1. Parameter Grd (for stepped thermowell only):

2. Stress concentration factor:

• Other connections:

1. Stress concentration factor at support plane (for stepped thermowell only):

2. Temperature de-rating factor:

8. Calculate Frequency Limit

• Low density gases: Nsc >2.5 and Tr ,100000

• General case: Other values of Nsc and Re

9. Compliance with the frequency limit requirement:

1. Initial evaluation of compliance:

• The thermowell is in compliance with the frequency limit requirement if;

Go to step 10.

• The thermowell is non-compliant with the frequency limit requirement if;

Go to step 10.

1. Evaluate compliance with cyclic stress limit for general case:

• Calculate velocity for in-line resonance:

1. Calculate cyclic drag stress at the root:

2. Calculate combined drag and lift stresses:

3. Calculate fatigue stress limit:

4. Compliance with cyclic stress limit:

• Tapered and straight thermowell:

• Not compliant with the cyclic stress limit and frequency limit if;

Go to step 10.

• Complies with the cyclic stress limit if;

Set new frequency limit:

Go to step 9g

• Stepped thermowell:

• Not compliant with the cyclic stress limit and frequency limit if;

Go to step 10.

• Case

Calculate:

• Not compliant with the cyclic stress limit and frequency limit if;

Go to step 10.

• Complies with the cyclic stress limit if;

Set new frequency limit:

Go to step 9-g.

1. Re-evaluate compliance with the frequency limit requirement if cyclic stress is acceptable:

• The thermowell is in compliance with the frequency limit requirement if;

• The thermowell is in non-compliant with the frequency limit requirement if;

10. Compliance with the static stress limit requirement:

*B[m], P[Pag], S[Pag]

1. Calculate radial, tangential, and axial stress due to external pressure:

2. Calculate steady-state drag stress at the root:

3. Calculate steady-state stress due to the drag force:

4. Calculate maximum stress:

5. Calculate left-hand side of the Von Mises criteria:

6. Calculate right-hand side of the Von Mises criteria:

Compliance

• Tapered and straight thermowell:

• Not compiled with the static stress limit if;

• Complies with the static limit if;

• Stepped thermowell:

• Not compiled with the static stress limit if;

• Case

Calculate:

• Not compliant with the static stress limit if;

• Complies with the static stress limit if;

11. Compliance with the Dynamic Stress Limit requirement

Calculate parameters:

12. Calculate drag and lift stresses at the root:

13. Calculate combined drag and lift stresses:

14. Calculate fatigue stress limit:

Compliance

• Tapered and straight thermowell

• Not compliant with the dynamic stress limit if;

• Complies with the dynamic stress limit if;

• Stepped thermowell

• Not compliant with the dynamic stress limit if;

Go to Compliance with the Hydrostatic Pressure Limit requirement section in this topic

• Calculate:

• Not compliant with the dynamic stress limit if;

• Complies with the dynamic stress limit if;

15. Compliance with the Hydrostatic Pressure Limit requirement

*B[m], P[Pag], S[Pag]

16. Calculate pressure rating for the shank:

17. Calculate external pressure rating for the tip:

18. Calculate pressure rating of the thermowell:

19. Compliance

• Not compliant with the hydrostatic pressure limit if;

• Compliant with hydrostatic pressure limit if;