Experimental investigation of air step cooling by the combination of spray and chord grid for mine cooling

To address the issues of heat and humidity hazards, as well as insufficient air volume in deep mining operations, a novel cooling method combining spray and chord grid is proposed. To investigate the cooling dynamics, an experimental platform integrating both spray and chord grid components is independently developed. Field boundary conditions are simulated to conduct orthogonal experimental research. Under the experimental parameters of an inlet air temperature of 32°C, relative humidity of 88%, and initial spray water temperature of 26°C, the effects of water-air ratio, nozzle distance, and other parameters on inlet and outlet temperature, as well as moisture content, are quantified. These influencing factors are analyzed through range analysis. Results demonstrate that the water-air ratio has a greater impact on cooling compared to the nozzle distance. Notably, when the water-air ratio and nozzle distance reach critical values of 0.6 and 70cm respectively, the cooling rate begins to plateau. Furthermore, comparative analysis of the cooling and dehumidification effects of single spray versus spray + chord grid reveals that the cooling capacity of single spray systems can be surpassed by incorporating a chord grid. Specifically, the combination of spray + chord grid achieves superior cooling effects with lower water consumption.