VOL. 13, NO. 3, FEBRUARY 2018 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences ©2006-2018 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 929 PERFORMANCE EVALUATION OF FLUID FLOW IN A STRAIGHT PIPE OF HEAT EXCHANGER Nurul Amira Binti Zainal, Ariff Bin Md Sullah, Ezzatul Farhain Binti Azmi and Muhammad Shahril Bin Ahmad Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka, Malaysia E-Mail: nurulamira@utem.edu.my ABSTRACT Heat exchanger is an important device in all thermal systems. It is widely used equipment in numerous industries such as process control, petroleum refining, chemical industry, heat recovery systems and much more. Energy and material saving considerations as well as environmental challenges in the industry nowadays have stimulated the demand for high efficiency of the heat exchanger. To improve the efficiency of the heat exchanger, heat transfer performance enhancement in the heat exchanger must be considered. This study is carried out to investigate and examine the fluid flow in a straight pipe heat exchanger with thermal designing and analysed by using SolidWorks software. Three different materials of the heat exchanger are used which are copper, stainless steel and brass to identify the best material of a straight pipe heat exchanger. The heat exchanger is set to be oil-water heat exchanger model. The fluid flow properties in the pipe of heat exchanger are simulated with computerized simulation to recognize the best material of heat exchanger. There are two parameters that take into consideration in this study, which are temperature and pressure distributions. Through the simulation results, copper shows the most efficient heat transfer compared to stainless steel and brass. This implies that, copper is the most efficient heat conducting and it can be concluded that the effects of different material and fluid flow in the pipe and in the cylinder of a straight pipe heat exchanger definitely able to enhance the performance of the heat exchanger. The analysis of the findings of this study is presented in this paper. Keywords: fluid flow, straight pipe, thermal systems, oil-water heat exchanger. INTRODUCTION The heat exchanger is an important device in various thermal systems, for example condenser and evaporation in a refrigerant system, boiler and condenser in steam power plants and etc. It is used to transfer the heat from the hot fluid to cold fluid with maximum rate and minimum investment. The heat exchanger is widely used in industrial applications such as process industries, chemical industries, food industries and etc. Vitality and material sparing contemplations and natural difficulties in the business have re-enacted the interest for high productivity of heat exchanger. Continuous improvement of heat exchanger empowers the span of heat exchanger to be significantly diminished. A higher rate of heat exchange with low space prerequisite is needed for minimizing warmth exchanger. Nowadays, there are several types of heat exchanger had been introduced, for example plate heat exchanger, plate and shell heat exchanger, plate fin heat exchanger, double pipe heat exchanger, shell and tube heat exchanger and straight tube heat exchanger. However, this study is focused on a straight pipe heat exchanger. The straight pipe heat exchanger is one type of heat exchanger which is designed with simple straight tube. It is commonly found in steam generator at the power plant. In other word, it is a sub of shell and tube heat exchanger type. This straight tube was made in the shell with baffle. Figure-1 shows an example of a straight pipe heat exchanger. Figure-1. Example of a straight pipe heat exchanger with inner pipe. PRINCIPLE OF HEAT EXCHANGER The transfer of heat between same or different two or more fluids is the basic principle of heat exchanger. Two fluids are brought in close contact with each other, but are prevented from mixing by a physical barrier. The scientific physical fluid is separated by heat transfer surface, which is transferred from the hot to cold agent (Nawras, 2014). The temperatures of the two fluids soon come to an equilibrium temperature (Agarwal et al., 2014). The energy from each fluid is exchanged and no extra heat is added or removes (Raskovic et al., 2010). It is known that the heat transfer capacity and cost of a waste heat recovery system is directly related to its size and thermal performance (Soylemez, 2008). Appropriately, the heat exchanger must be designed in a way that it is suited for all cases of heat exchange since the heat in the process and the heat amount of the fluids are not constant. The procedure for optimal heat exchanger design includes estimation of the exchanger heat transfer area based on the required duty and other design specifications (Caputo et