Thermal Performance Enhancement of Shell-and-Tube Heat Exchangers Using Variable Helical Baffle Configurations

Abstract

Shell-and-tube heat exchangers are among the most widely utilized thermal energy transfer devices in power generation, chemical processing, petroleum refining, refrigeration, food processing, pharmaceutical manufacturing, and HVAC systems due to their structural simplicity, high-pressure tolerance, operational reliability, and ease of maintenance. However, conventional segmental baffle arrangements often generate significant shell-side pressure losses, flow stagnation zones, vibrationinduced tube damage, and inefficient fluid mixing, thereby limiting the overall thermal performance of the heat exchanger. Recent developments in helical baffle technology have demonstrated considerable potential for improving shell-side flow distribution by promoting continuous spiral fluid motion, reducing dead zones, minimizing fouling, and enhancing convective heat transfer. Nevertheless, existing fixed helical baffle configurations are unable to adapt to varying thermal loads and operating conditions, resulting in suboptimal heat transfer efficiency under different flow regimes. To overcome these limitations, this paper proposes a Variable Helical Baffle Configuration (VHBC) for shell-and-tube heat exchangers, in which optimized helical angles and variable baffle spacing are strategically designed to maximize heat transfer while minimizing pressure drop and pumping power. The proposed methodology integrates Computational Fluid Dynamics (CFD), thermal-fluid numerical modeling, turbulence analysis, and multi-objective optimization to evaluate shell-side flow characteristics, temperature distribution, velocity profiles, turbulence intensity, and overall heat transfer performance under varying operating conditions. Numerical investigations demonstrate that the variable helical configuration significantly enhances shell-side fluid mixing, increases turbulence uniformity, improves temperature distribution, reduces recirculation regions, and lowers pressure loss compared with conventional segmental and fixed helical baffle arrangements. Experimental validation confirms improvements in heat transfer coefficient, Nusselt number, thermal effectiveness, overall heat transfer coefficient, and thermo-hydraulic performance while simultaneously reducing energy consumption and pumping requirements. The proposed variable helical baffle design provides a highly efficient, reliable, and economically viable solution for next-generation shell-and-tube heat exchangers operating in energy-intensive industrial applications requiring superior thermal performance, reduced operational costs, and enhanced system sustainability.