ISSN(Online): 2319-8753 ISSN (Print): 2347-6710 International Journal of Innovative Research in Science, Engineering and Technology (An ISO 3297: 2007 Certified Organization) Vol. 4, Issue 1, January 2015 DOI: 10.15680/IJIRSET.2015.0401025 www.ijirset.com 18591 Experimental Study of Flow Characteristic at Horizontal Mini Channel Othman Ashafai Othman Atpoly 1 , Budi Santoso 2 , Dwi Aries 2 , Ammar Mufrih 2 , Latif Ngudi Wibawanto 2 1 P. G. Student, Post Graduate Program of Mechanical Engineering, Sebelas Maret University, Indonesia 2 Department of Mechanical Engineering, Sebelas Maret University, Indonesia ABSTRACT: The small or mini channel is widely adopted in compact heat exchanger in particular. In present study, the values of velocity and gas void fraction in two-phase gas-liquid flow in mini-channels were experimentally determined. The depth and width of the rectangular cross-section of the channel were 3 mm x 3 mm and 3 mm x 6 mm. The investigated flow and channel size to be applied in measurements of velocity and gas void fraction, a method based on the digital image analysis was applied. The value of gas phase velocity was defined by the values of distribution parameter C 0 . The relation describing the value of gas void fraction depended on the Bankoff coefficient and gas input volume fraction. KEYWORDS: Two phase flow, Flow pattern, Bubble velocity, Horizontal mini channel, Void fraction. I. INTRODUCTION The flow of two phases (air and water) is related to many device and application such as power generator unit, nuclear industry, micro electric device, etc, which occurred heat transfer on all of it. This condition makes a great demand in optimizing the efficiency of heat exchanger design by heat removal techniques to dissipate increasingly large heat flux. The use of air and water as the working fluids at two-phase flow with mini rectangular channels will conduct in this research to know the effect of channel size. The main parameters are void fraction or superfractial velocity or bubble velocity at horizontal mini channel. The investigation of flow phenomena in a mini channel is very important since this kind of application is used as heat exchanger. The differences between the vertical and the horizontal channel cause noticeable differences in the measured parameters in the annular flow region where J G is larger than about 10 ms −1 [1]. Huang et al. [2] described a method for the identification of gas-liquid two-phase flow regime in mini-pipes based on textural feature series. A high-speed image acquisition system is used to capture images of gas-liquid two-phase regimes in the mini-pipe and five typical flow regimes (stratified flow, wavy flow, bubbly flow, slug flow and annular flow) are observed. Based on description that has been mentioned above, the researcher is interest in studying about the two-phase flow air and water at rectangular mini channel due to the characteristics. II. THEORY An air-water mixture flow in a pipe can exhibit a variety of shapes and distributions of interfacial surfaces which can be used to determine the characteristics of the flow. The flow patterns have direct effect on the pressure drop and the heat transfer characteristics of the fluid. A view of flow patterns is shown Fig. 1. Data collected from observations of flow patterns can be expressed in a flow pattern map. This flow pattern maps are used to determine the flow patterns that occur based on the given conditions. Mandhane et al. [3] makes the flow pattern map with the coordinates of the superficial liquid velocity (J L ) and superficial gas velocity (J G ) divided into patterns of bubble flow, plug, stratified, wavy, slug, and annular.