A Numerical Study on Enhancement of Heat Exchanger Performance by Inserting Static Mixer Elements

Abstract

In chemical processing industries, heating, cooling and other thermal processing of viscous fluids are an integral part of the unit operations. Static mixers are often used in continuous mixing, heat transfer, and chemical reactions applications. Generally, a static mixer consists of a number of equal stationary units, placed on the inside of a pipe or channel in order to promote mixing of flowing fluid streams. These mixers have low maintenance and operating costs, low space requirements, and no moving parts. A range of designs exists for a wide range of specific applications. The shape of the elements determines the character of the fluid motion and thus determines the effectiveness of the mixer. There are several key parameters in the design procedure of a static mixer. An ideal static mixer for heat transfer applications provides a higher rate of heat transfer and thermally homogenous fluid with low pressure drop and similar traveling history for all fluid elements. To choose a static mixer for a given application or in order to design a new static mixer, besides experimentation, it is possible to use powerful computational fluid dynamics (CFD) tools to study the performance of static mixers. This paper illustrates how static mixer can improve the performance of heat exchangers. Using different measuring tools, the global performance and costs of two popular commercial static mixers are studied in order to choose the most effective design for thermal applications.