Recently,i use WRC107 included in CAESAR2 to check nozzle load ,if not include the internal pressure trust ,the result can be passed .Is this method suitble?
IF include the internal pressure trust ,it will have great influence on the result ,not passed. so how and when to choose this option?

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The pressure thrust load does not really fit a "Yes" or "No" sort of question - it's not all on or all off. What I might suggest - for the WRC check alone - is to model the pressure thrust that may act on the nozzle as a load (F1) [mostly on the first elbow beyond the nozzle but other surfaces may be loaded as well]. Add this force set to the load case you are evaluating and then the pressure that actually finds its way to the nozzle will be part of that boundary load.