Design and Performance Evaluation of a Shell-and-Tube Exhaust Gas Recirculation Cooler Using Kern Method With Experimental Validation on a Diesel Engine

Abstract

Abstract. Efficient thermal management in modern diesel engines is crucial for enhancing performance, reducing emissions, and meeting stringent environmental regulations. This study presents the analytical and experimental evaluation of a shell-and-tube exhaust gas recirculation (EGR) cooler designed using the Kern method to estimate the overall heat transfer (OHT) coefficient, effectiveness (ε), and tube-side pressure drop (ΔP). The cooler consists of 24 copper tubes (8 mm outer diameter, 220 mm length) arranged in a triangular pitch with baffles featuring a 45% cut. A novel tube bundle configuration, limiting the center row to four tubes in a symmetric (1-4-5-4-5-1) pattern, is proposed to alleviate central flow congestion. Analytical predictions yielded an OHT coefficient of 64 W/m2 K, while experimental testing on a single-cylinder diesel engine reported an average value of 53.56 W/m2 K. Results demonstrated that effectiveness decreased with increasing exhaust flowrates but relatively found higher in case baffles suggesting the incorporation of baffles significantly enhanced heat transfer performance. Experimental results with analytical estimates of pressure drop 0.75 kPa and 0.7 kPa for without and with baffles indicate comparable heat transfer performance with a reduced tube-side pressure drop, suggesting improved flow uniformity and lower core resistance, thus validating its potential for compact, high-performance, and emission-reducing EGR systems in diesel engines.