Actual loads on nozzles during operation. Possible to measure? 1

[babooman]

Dear all,

In a ruuning plant, we would like to determine the actual loads imposed by the piping system on the nozzles of one pump. We do have a piping stress model (Caesar) but are interested in measuring the actual loads during operation, not using simulation, FEA, etc.


Any of you is aware of any technoloy or method to do that?


Thank you for the help.

 

[goutam_freelance]

Yes but indirectly. It is possible to calculate nozzle stresses at surface by using suitable strain gauges. After getting strains at representative points nozzle loads can be calculated using theory of elasticity formula or Roark formula.Strain difference at no load and full load needs to be calculated.

 

[Strong]

I did this a long time ago on 2000 hp boiler feed water pump. You can measure both axial and bending strain in two directions with stain gages and low noise amplifiers. The measurement baseline has to be established a machine off and stable temperature.

Walt

 

[KevinNZ]

I have seen the effect of nozzle loads on the displacement of a turbine shell measured with a special camera set up.

 

[engrom]

Thanks - any references of companies (global or APAC region) who can do such quantification of nozzle loads (stresses) using the techniques mentioned above (i.e. strain gauge, load cell, camera...)?

 

[rb1957]

I'd go visit a local university, one with a "good" engineering program. They usually like helping industry.

I'd use FEA to show a region of uniform stress.

Another idea, I don't know how feasible this is, would be to put very stiff calibrated springs between the piping and it's supports. Would the piping permit say 0.25" deflection ?

another day in paradise, or is paradise one day closer ?