1引言蒸汽排空噪声是化工、炼油和火力发电厂常见的噪声级超过100dB（A）的少数噪声源之一。尽管蒸汽排空是间歇性和短时间的，但它高强度尖啸刺耳的噪声事实上已成为影响厂区工人和附近居民正常工作和生活的一大“公害”。近年来，国内不少单位采用扩容降压和小孔喷注的设计原 1 INTRODUCTION Steam emission noise is one of the few noise sources commonly found in chemical, oil refining and thermal power plants that exceed 100 dB (A). Although the steam evacuation is intermittent and short-term, its high-pitched and jarring noise has in fact become a major “nuisance” affecting the normal work and life of factory workers and nearby residents. In recent years, many domestic units to expand the use of pressure relief and orifice injection design of the original