STV-12 Updated Methods to Predict Acoustic Vibration in Heat Exchangers
Current heat exchanger design trends toward larger diameters and higher fluid velocities increase the likelihood of acoustic resonance. Thus, the potential for acoustic vibration must be assessed reliably during the design phase. Coincidence of the excitation and acoustic frequencies of the shell is a necessary but not sufficient condition for acoustic resonance. Enough energy must be deposited in the shellside fluid before acoustic vibration can occur. Several methods of quantifying a threshold value for this energy exist. This report examines two such methods, developed by Ziada and by Eisinger, and, using a number of cases in HTRI’s vibration data bank, compares them to the method used in Xist™ 1.0. The Eisinger method results were found to be nearly equivalent to those of the current HTRI method. The Eisinger approach, however, includes an assessment for higher throughputs and higher modes—valuable information for a process engineer faced with altering the flow rate through an exchanger. Consequently, the Eisinger method will be included in a future version of Xist for a more comprehensive acoustic vibration assessment.