Journal of Thermal and Fluid Science (JTFS)
Volume 7 · Issue 2 · August 2026 · pp 21-28
Research Article · Peer Reviewed
Received: May 12, 2026 · Accepted: July 30, 2026 · Published: August 11, 2026
DOI: 10.26706/jtfs.7.2.20260801
Open Access · CC BY 4.0

Characterization of the Combustion Chamber Reactor Flow Field in a Small-Scale Carbon Black Plant

Shrikant Vijay Pawar1*, Dr. Nitin Kardekar2

1 Research Scholar, Department of Mechanical Engineering, Sunrise University, Alwar, India.
2 Associate Professor, Department of Mechanical Engineering, JSPM NTC, Pune, India.

*Correspondence: shrikant1474@gmail.com

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Abstract

Furnace-black carbon black production relies on tight control of the internal aerodynamics of the combustion chamber and reactor to obtain a uniform, well-mixed, and correctly conditioned flow of feedstock, fuel, and combustion air; poor internal flow quality is a recognised cause of non-uniform particle residence time, localised over- or under-conversion, and wall fouling. This paper reports a three-dimensional computational fluid dynamics (CFD) characterization of the combustion chamber and downstream flue-gas duct of a small-scale carbon black reactor unit, undertaken as a baseline verification step ahead of hardware fabrication. Under representative operating conditions—an air-fuel mixture entering at 0.079 kg/s and 1350°C, secondary combustion air totalling 0.2156 kg/s at 250°C admitted through two ports, and an operating pressure of 101325 Pa—the geometry was discretised into approximately 3.9 million cells with near-wall inflation layers sized to achieve an average wall y+ of unity (maximum 3.17 at the reactor inlets). Global mass and energy balances closed to within 1% (0.3035 kg/s in versus 0.30352 kg/s out; a 526 W imbalance against a combined thermal input of 398.6 kW), supporting confidence in the converged solution. Post-processed velocity, temperature, and pressure fields show secondary air accelerating through the reactor choke to a peak local velocity of 89.43 m/s, together with a static and total pressure recovery of 201.05 Pa and 295.85 Pa at the reactor outlet. Critically, the analysis reveals persistent, wall-adjacent dead zones and toroidal recirculation cells at the point where the air-fuel mixture enters the combustion chamber, attributable to an abrupt step-change in cross-section at that location. These findings establish a quantitative baseline flow field and identify a specific, geometrically localised deficiency that motivates a targeted redesign, evaluated separately.

Keywords

computational fluid dynamics carbon black combustion chamber reactor baseline characterization recirculation dead zone mass and energy balance wall y+

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