TECHNICAL ARTICLE—PEER-REVIEWED Numerical Analysis of Hot Air Recirculation Phenomenon in a Compressor Unit and Prevention of Overheating A. M. Khalaf . I. Barsoum Submitted: 8 April 2019 Ó ASM International 2019 Abstract Managing the hot air recirculation and flow pattern in air-cooled systems is essential for satisfactory performance and reliable operation of compressor units. In this study, a numerical analysis of the exhaust air from an air-cooled compressor package located in oil and gas off- shore platform is presented using computational fluid dynamics. The results of the analysis reveal that hot air recirculation can have a direct impact in air-cooled units, which is associated with the installation arrangement of the mechanical packages involving air coolers and the envi- ronmental conditions around the units. The results were able to predict flow and temperature fields in the com- pressor area, and provided recommendation to avoid exhaust air recirculation, which if not addressed and pre- vented can greatly reduce the cooling effectiveness of the air coolers leading to less reliable systems. Keywords Air-cooled Á Heat exchanger Á Compressor Á CFD Á Hot air Á Recirculation List of Symbols q Density (kg/m 3 ) u Velocity vector (m/s) g Gravitational constant (9.81 m/s 2 ) l Dynamic viscosity (Pa s) c p Specific heat at constant pressure (J/g K) _ q Rate of heat generation per unit volume (W/m 3 ) K Thermal conductivity (W m À1 K À1 ) ß Thermal expansion coefficient (K À1 ) U Viscous dissipate rate (J/kg s) R Universal gas constant = 8.314472 J/K.mol _ m Mass flow (kg/s) T Temperature (K) DT Change in temperature (K) T in Cooler fan inlet temperature (K) T out Cooler fan outlet temperature (K) T a Atmospheric ambient temperature (K) F z Buoyancy force (N) R HAR Hot air recirculation ratio R HAR Average hot air recirculation ratio Introduction Air-cooled heat exchangers (ACHE) are commonly used in industrial applications such as electrical power generation plants, petrochemical processing areas, and in data centers involving high-temperature IT equipment [1–4] due to economic and environmental considerations [5]. The ther- mal management of critical equipment including air-cooled condensers in power plants, power transformers, and gas compression systems is crucial, and the associated cooling systems highly contribute to the reliability and efficiency of the overall plant [6–8]. Although air-cooled systems may require less cost compared to water-cooled systems, their optimum performance will depend on several factors such as wind direction and speed, flow obstructions, environ- mental conditions, i.e., changes in ambient conditions, and hot air recirculation [1]. All these factors have a significant effect on the heat transfer ability, especially in controlling A. M. Khalaf Central Engineering Department, CED, Abu Dhabi National Oil Company (ADNOC Offshore), P.O. Box 303, Abu Dhabi, UAE e-mail: amkhalaf@adnoc.ae I. Barsoum (&) Department of Mechanical Engineering, Khalifa University of Science and Technology, P.O. Box 2533, Abu Dhabi, UAE e-mail: imad.barsoum@ku.ac.ae 123 J Fail. Anal. and Preven. https://doi.org/10.1007/s11668-019-00700-3