S.M Modarres - PhD, Researcher in Mechanical Engineering Department, Imam Hossein Comprehensive University, Tehran, Iran.
M. R. Najafi - PhD Student, Mechanical Engineering Department, Imam Hossein Comprehensive University, Tehran, Iran

Nano emulsions which contain nano sized dispersed phase(s), have many applications in in-dustries such as petroleum, food, pharmaceutics, intinctions, lubrication, etc. Irradiating ultra-sound waves by vibration of piezoelectric ceramics (PZTs) through the emulsion, which called ultrasonic emulsification (UE), is one of the most effective and efficient methods for preparing homogenous, uniform and steady nano emulsions. This review paper assigned for the wide ranging researches discovered through the parameters related to ultrasonic emulsification such as irradiation frequency, power, amplitude and its duration. Also, ultrasonic emulsification methods are investigated. It discourses studies exploited ultrasonic emulsification with further methods, concurrently and autonomously, and also its constraints optimization is considered. This plan has an imperative role to understand undiscovered aspects of this field leading to use optimized parameters. The researches indicate that ultrasonic emulsification with enhanced features and with a capability to simulate the conditions is a desired method which will gain access more improvements

Nanoemulsions, Irradiating ultrasonic waves, Ultrasonic emulsification; irradia-tion factors; surfactant-free nanoemulsions