Thermal and Flow Analysis of Different Shaped Pin Fins for Improved Heat Transfer Rate Nhad K. Frhan Al-Abboodi 1 , Kamil Abdulhussien Khalaf 1 , Huda Ridha 2* , Mohammed G. Al-Azawy 1 1 Mechanical Engineering Department, College of Engineering, Wasit University, Wasit 52001, Iraq 2 Veterinary Medicine College, Wasit University, Wasit 52001, Iraq Corresponding Author Email: hridha@uowasit.edu.iq https://doi.org/10.18280/ijht.400124 ABSTRACT Received: 28 January 2022 Accepted: 25 February 2022 In this paper, a micro pin fin heat sink is numerically investigated with four fins geometries (circular, elliptical, square, and drop shape) at two types of arrangement styles, inline and staggered arrangement. The hydrodynamic and thermal characteristics of different fin geometries and two arrangement styles have been compared under the exact value of Reynolds number and constant wall temperature thermal boundary conditions. The Reynolds number was sweeping in the range of (400-2800) to ensure the fluid flow velocity impact in the pin fin performance. The results obtained indicate that a longitude pin fin dropped with increasing Reynolds number at a distributed temperature. Also, the circler Pin fin reaches the lowest temperature comparison to the rest of the three-pin fin types. Generally, according to the extracted, Nusselt number for different geometries increased versus increasing the Reynolds number. Observe that the elliptical fin shape yields the highest Nusselt number at all Reynolds numbers. Moreover, the elliptical pin fin ejects the highest heat transfer rate, which indicates the pin fin performance. Furthermore, skin friction has a significant function with variation in Reynolds number. Keywords: fins configurations, fins profile geometric, CFD, Nu, Re, drag force 1. INTRODUCTION Microelectronic systems must be able to dissipate significant heat flux to maintain stable and optimal performance due to the rapid growth of today's electronic device production. Numerous ways have been developed to meet this need, including a micro channel heat sink with various fin shapes and arrangement styles. New and improved access will need to be considered to maintain the increasing trend the heat extraction. Because of their tiny mass and volume and more excellent surface-to-volume ratio, these heat sinks of the micro channel are ideal for cooling chips with high heat flux. Pin fins with various shapes and configurations have been presented to increase the cooling capacity and the temperature symmetry of this technology. Increasing the external heat dissipating area, which is extended surfaces, is one of the primary functions of the fins. The different pin fins and additional arrangements are used to enhance the micro heat sink's efficiency. Several investigation studies were found in the literature to truly comprehend a micro-pin fin heat sink's flow and heat transfer features. It was found that the most common pin fin shapes (round, elliptical, and square), as well as the staggered and inline configuration of the plate fins, amplifier the heat sink's ability to dissipate energy effectively. Staggered geometries outperformed inline in all circumstances, while elliptical fins performed best at a low-pressure loss and pumping power levels. Rounded pin fins work well at high power values, Feng et al. [1]. Pin fin heat sinks with fins in various forms (circular, square, and triangular) were empirically studied by Ricci and Montelpare [2]. According to their findings, triangle geometry was the best of the rest. Shaeri and Yaghibi [3] explored a flat plate with a flat array of solid and perforated fins and an incompressible air working fluid based on the numerical simulation method. Compared to solid fins, longitudinal straight protruding fins have a remarkable heat transmission increase and a significant weight decrease. Micro square pin fin heat sinks with staggered configuration were explored by Ambreen et al. [4]. The authors use water for cooling with a Reynolds number varying from 60 to 800. Nusselt number and pressure loss rose with Re, but heat resistance dropped with pressure loss. It was found that the use of nanofluid in a micro pin fin heat sink had a positive influence on its performance. Investigated the effect of two nanofluids (diamond-water and Al2O3-water) for the heat sink with three types of pin fin geometry (square, triangular, and round) Mushtaq [5]. The results reveal that nanofluid improves thermal performance as well as lowers pressure. Moreover, the authors reported that circular fins have a greater heat transmission rate than the other fins. Yacine et al. [6] conducted a numerically study to evaluate the different pin fine geometry and fluid flow velocity effect on the pin fine's pressure losses, heat transfer coefficient, and temperature distribution. The computation fluid dynamic (CFD) solver using the k-ε turbulence model. The authors reported that the smaller spaces between the pin fins increase the pressure dropping, improve heat transfer, and maximize heat transfer rate, Baruah et al. [7] Performed a numerical study to analyze and investigate the heat transport rate for the solid and perforated elliptical pin fins in various applications. The elliptical pin fins are designed with three elliptical cross- section holes. The computational domains accounted for various intake velocities, different pressure, temperature, and velocity profiles. There is a significant improvement in heat transmission, while pressure decrease with the perforated fins over the solid elliptical pin fins. Ahmadian-Elmi et al. [8] conducted experimental studies to evaluate design parameters' International Journal of Heat and Technology Vol. 40, No. 1, February, 2022, pp. 201-210 Journal homepage: http://iieta.org/journals/ijht 201