Uneven airflow distribution among vertically stacked servers is a persistent cause of top-of-rack hot spots in backplane air-conditioned (backplane-AC) data center cabinets, where buoyancy-driven recirculation starves the uppermost servers of cooling air while lower servers remain over-supplied. Existing mitigation strategies reported in the literature are almost exclusively active, relying on fan-speed redundancy, gradient exhaust profiles, or blind plates, all of which require additional control hardware and energy input. This paper numerically investigates a purely passive alternative: an internally mounted, angled baffle deflector placed in the backplane exhaust plenum. A reduced-order, flow-network model of an eight-server cabinet is developed, coupling branch-level mass and momentum balances with an empirical turning-vane loss correlation that captures the influence of baffle deflection angle (30°, 45°, 60°) and plate shape (flat plate, curved vane) on the local loss coefficient. Six configurations — a no-baffle baseline and five baffle variants — are solved for airflow uniformity, rack pressure drop, fan power consumption, and server inlet temperature spread under a fixed total airflow rate. The results show that every baffle configuration improves all four metrics relative to the baseline, with improvement increasing monotonically with angle and always favoring the curved vane over the flat plate at equal angle. The best-performing configuration (curved vane at 60°) raises the Uniformity Index from 0.932 to 0.985, reduces the coefficient of variation of server velocity from 6.77% to 1.47%, cuts rack pressure drop and fan power by 16.3%, and narrows the top-to-bottom temperature spread from 0.37 °C to 0.01 °C. These consistent, mutually reinforcing gains indicate that a simple, low-cost, maintenance-free geometric modification can rival active fan-control strategies for hot-spot mitigation while simultaneously improving energy efficiency.

Fazlur Rahman, Chaitanya Shrivastava, Dr. Raghvendra Kumar Khedle, "Numerical Evaluation of Internal Baffles for Airflow Uniformity in Data Center Cabinets" International Journal of Scientific Research and Engineering Development, V9(5): Page(574-585) September - October 2026. ISSN: 2581-7175. www.ijsred.com. Published by Scientific and Academic Research Publishing.