Short-wave infrared heater with a nanofluid collector that includes internal arrays of round nozzles - Irreversibility Analysis

University of Tuzla, Faculty of Mechanical Engineering, Department of Thermal and Fluid Technique, Bosnia and Herzegovina

Abstract

Short-wave infrared radiation allows for efficient heating of a body (target) with minimal thermal interaction with the gaseous medium through which it passes. The mutual geometric relationship between the infrared heating source and the target impacts the spatial resistances of radiation heat transfer. Therefore, a significant portion of the short-wave infrared radiation emitted by the heat source does not reach the target, thereby reducing its efficiency. To maximize the use of thermal radiation, this study analyzes a profiled nanofluid collector on which a heated target is placed. Nanofluid with Al₂O₃ nanoparticles flows through internal arrays of round nozzles and a profiled housing, being heated by the inner surface of the collector. The paper establishes a methodology based on the thermal irreversibility of the heat source, collector and nanofluid. The established methodology allows for minimizing thermal entropy in order to optimize the geometric and process parameters of the described system. The results of the conducted analysis are based on the cross-influence of the Reynolds number of the nanofluid, target and collector emissivity, short-wave heating time and nanoparticle volumetric ratio. The results obtained indicate that as the target emissivity, heater temperature and heating time increase, the thermal entropy of the mutual interaction between the heater and the target also increases significantly. Similarly, the thermal entropy of the mutual interaction between the collector and the nanofluid is greatly influenced by factors such as the Reynolds number (from 2000 to 4000), volumetric ratio (3% and 5%) and type of nanoparticles used (Al₂O₃, TiO₂, and CuO). In this way, the specially designed collector allows for the utilization of captured heat, while the established methodology offers the opportunity to optimize the process-geometric parameters of the heating system being analyzed.