In heat exchangers, cold and hot fluid flow during heat exchange generates noise. This noise propagates through connected piping systems and considerably affects the acoustic stealth performance of vessels. With increasing flow rates and the trend toward larger-scale heat exchangers, noise issues have become more pronounced, highlighting the urgent need for effective noise control strategies. However, the underlying excitation mechanisms, noise sources, and radiation characteristics of flow-induced noise in liquid-cooled heat exchangers remain poorly understood. This gap renders vibration and noise control efforts ineffective and insufficient to support the low-noise design of heat exchangers. To address this gap, herein, we performed numerical analysis using computational fluid dynamics and acoustic analogy theory. Noise levels were calculated under both shell-side and tube-side flow conditions. A comparative analysis revealed that heat exchanger noise is primarily driven by shell-side flow excitation, specifically, the sound pressure level of noise induced by shell-side flow is approximately 26 dB higher than that induced by tube-side flow. Furthermore, under shell-side excitation, the radiated noise at the tube-side inlet and outlet is about 5 dB higher than that at the shell-side ports. Considering that the tube-side passages are directly connected to the vessel’s seawater piping system, this finding underscores the critical necessity of investigating and mitigating heat exchanger noise. Further, the contributions of different structural panels within the heat exchanger were analyzed. Color-mapped diagrams depicted the noise contributions of individual panels. Based on vector projection, a normalized panel contribution evaluation method was established to enable quantitative comparisons of the contributions of structural panels across different frequencies. The results indicated that acoustic radiation generated by heat exchanger tube vibrations constitutes the dominant noise source. Finally, experimental measurements were conducted to verify the accuracy of the numerical calculations. Overall, this study’s findings clarify the mechanism of flow-induced noise generation in heat exchangers and guide low-noise heat exchanger design, thereby supporting improvements in acoustic stealth performance.
Chen et al. (Fri,) studied this question.