Mathematical modelling of heat and hydraulic processes in a solar air heater with a concave air duct absorberBekzod Abdukarimov, Muxammadrafiq Toxirov, Obido Jamshidov and Sardorali MirzayevE3S Web of Conf., 452 (2023) 04007DOI: https://doi.org/10.1051/e3sconf/202345204007