VOL. 12, NO. 8, APRIL 2017 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2017 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 2556 INVESTIGATE THE BEHAVIOUR OF WATER MIST SPRAY WITH LOW PRESSURE APPLIED FOR KITCHEN VENTILATION EXHAUST (KVE) SYSTEM M. Farid Sies, M. Syiraj Mustafa, Nor Adrian Nor Salim, Hanis Zakaria and Norzelawati Asmuin Department of Engineering Mechanics, Universiti Tun Hussein Onn Malaysia, Malaysia E-Mail: farids@uthm.edu.my ABSTRACT This paper will focus on the behaviour of mist spray using the internal mixing twin fluid atomizer (Delavan AL75) with a different pressure of fluids. The cleaner nozzle selection should be emphasized intended to provide a healthy environment in an indoor cooking area that reduce the pollution and wastage. The kitchen exhaust ventilation system is the process of neutralizing the contaminated air in the cooking space through the cleaning process. The pressure of fluids in this study is 1bar, 2bar and 3bar at room temperature of 25 Ԩ to 30 Ԩ with humidity of 65% to 70%. The direct image analysis technique applied in analysing each picture of spray taken using the camera 550D/T2i then the image transfer to Solidworks for measure spray angle and penetrations. From the analysis, there was a mist spray formation in the form of cone angle with elongation penetration is low and spray angle increased wider than the existing nozzle. The behaviour of mist spray can be summarized when the air pressure increases, flow decreases and increases atomiser formation. The type of internal mixture nozzle can be applied for kitchen hood cleaning process. Therefore, the water consumptions can be reduced in kitchen ventilation hoods water wash (KVE-WW). Keywords: mist spray, direct image analysis, spray angle, spray penetration, water, air liquid ratio. INTRODUCTION The technology of Kitchen hood was introduced a new system and their ability enhanced from various areas. These developments are included the performed for improving the quality of food service and environment. It will start from initial concept through the solution of development, manufacturing, and installation on site, phase commissioning and maintenance. Every research and development need to have a classification and objective distinctive for example in terms of energy efficiency, indoor environment quality (IEQ), food or fire safety and air purification. The focus is for entirely on a dirty airborne in kitchen ventilation exhaust during the cooking process and especially in the cleaning process [1]. The water wash technology in the kitchen hood system is the combination of water mist and the water wash system. The purpose of this concept is as a cleaning system in the inner surface kitchen hood. This system is for maintain the high levels of hygiene, facilitates cleaning of the filters, increasing the productivity, reduce water consumption and maintenance cost. The nozzle development has seen related to exhaust hood design. Most researchers were studied in nozzle design with analyse the sprayed behaviour and spray characteristic. Each measurement techniques have used the microscopic and macroscopic spray characterisation with various methods includes the optical method, electrical or mechanical techniques. Optical techniques are most commonly method because it was easy to analyse but very expensive. The spray characteristics can be obtained with an experimental technique based on the analysis such as direct photographic imaging [2]. LITERATURE REVIEW Generally, mist spray is related to water. Water mist spray is defined as 99% of the volume is droplets with a diameter below 1000 μm (Dvorjetski and Greenberg, 2004; Heskestad, 2003; NFPA 750, 2003), the mean diameter is 80–200μm and 99% of the volume are below 500μm diameter (Grant et al., 2000) or the median droplet size is below 100μm (Lentati and Chelliah, 1998)[3]. There are a few categories for flat fan spray nozzle types and it separated with code. According to a review from nozzle manufacturer that practicing in spray system; flat-shaped spray pattern has four types of dispersion categories. There are flat spray tapered with spray angle range from 15 o to 110 o , Flat even with spray angle range from 25 o to 65 o , Flat spray deflected type with spray angle range from 15 o to 150 o , and air atomizing flat spray deflected. The deflected-type flat spray nozzles are chosen because it produces a relatively even flat spray pattern of medium-sized drops. The spray pattern is formed by liquid flowing over the deflector surface from around orifice. The flat spray nozzle with a 0° spray angle produces a solid stream. These nozzles typically will produce the highest impact per unit area. The previous study by Robert Grisso (2009) had identified, the pressure is the most important parameters for create the spray pattern and it will generate the finer atomization which high pressure of fluids give consequence in the droplet size [4]. Flow patterns and nozzle design can provide the strong effects of the spray characteristics and behaviour [5][6].