Daniel Eilers

Strain Based AIV Evaluation

A framework for Acoustic Induced Vibration (AIV) evaluation is outlined which is based on estimating the pipe surface strain for an evaluation framework of structural fatigue. Critical to this approach is that the assessment is implemented with frequency based formulations. The frequency based formulation allows for more accurate determination of the pipe’s structure response and combining different sources, such as the valve and piping elements. The approach relies on internationally recognized standards as the core technology, in particular the IEC 60534-8-3 control valve aerodynamic noise prediction standard and the fatigue assessment in design codes, such as the ASME Boiler and Pressure Vessel code. These are augmented with system noise predictions using a non-dimensional testing based model for piping component noise predictions. Components of this approach have been described in previous papers and are presented here in a more complete form.Copyright

AIV Evaluation With Sound Pressure and Fabrication Quality Standards

Criteria for evaluating acoustic induced vibration damage (AIV) has been based on available data, often referred to as the Carucci-Mueller approach1. The Carucci-Mueller approach has been developed with several variances, but all approaches apply the internal sound power formula used with that original published data. However, the equation is an approximation to sound power which is used in very few other applications. This paper will show a correlation between the Carucci-Mueller data and the related design curve to one generated using the IEC 60534-8-3 Control Valve Aerodynamic prediction noise standard2. Additional corrections for fabrication quality will be reviewed. Using internal sound power and the coupling to pipe wall vibration, the resulting external sound pressure can be directly related to strain and thus fatigue failure criteria which are material based. Utilizing the IEC noise standard as well as standards which give corrections for fabrication quality can move the AIV evaluation techniques to methods that are documented in international standards.Copyright

Air flow measurement techniques applied to noise reduction of a centrifugal blower

The air flow in a centrifugal blower was studied using a variety of flow and sound measurement techniques. The flow measurement techniques employed included Particle Image Velocimetry (PIV), pitot tubes, and a five hole spherical probe. PIV was used to measure instantaneous and ensemble‐averaged velocity fields over large area of the outlet duct as a function of fan position, allowing for the visualization of the flow as it leave the fan blades and progressed downstream. The results from the flow measurements were reviewed along side the results of the sound measurements with the goal of identifying sources of noise and inefficiencies in flow performance. The radiated sound power was divided into broadband and tone noise and measures of the flow. The changes in the tone and broadband sound were compared to changes in flow quantities such as the turbulent kinetic energy and Reynolds stress. Results for each method will be presented to demonstrate the strengths of each flow measurement technique as well as ...