NUMERICAL SIMULATION OF ALUMINIUM PROFILES COOLING PROCESS
Partner - FERRAM STROJÍRNA s.r.o.
The aluminium profile cooling process must be fully under the control of water quench operators. In the production process, an aluminium profile leaves the extrusion die at a temperature of approximately 500–550 °C, which needs to be reduced to the required temperature of 200–250 °C in a relatively short time of 15–30 sec. This can be achieved by treating the profile surface with water-air spray cooling in the water quench using special nozzles.
FERRAM STROJÍRNA s.r.o. is one of the world’s leading producers of cooling equipment for extruded aluminium profiles. This company has developed a revolutionary shape of jets, which allow a large volume of water and air to be accelerated at low pressure so as to achieve the desired effect of heat being conducted away from the profile surface. The specially designed nozzle forms droplets of water, which are subsequently mixed with air. These droplets are then carried away by air flow and spray the profile surface, conducting the heat away, thus cooling the profile. The correct setting of the Water Quench varies according to the shape of each individual profile. This setting is largely dependent on the experience of operators, which makes repeatability and precision of this process harder. In new profiles with no preceding setting, this leads to a high scrap factor as a result of using the trial and error approach.
Within the European H2020 CloudiFacturing project, IT4Innovations and FERRAM STROJÍRNA s.r.o. cooperate in developing a numerical model to simulate the aluminium profiles cooling process. Given the need to include all important physical processes associated with the aluminium profiles cooling process, a numerical model of the whole Water Quench, containing seven separate sections each equipped with four rows of nozzles, needs therefore to be developed. In addition, each nozzle must be modelled down to the slightest detail, which leads to hundreds of millions of compute cells in the resulting numerical model. Such a complex model cannot be solved using generally available workstations in a reasonable time. Its solution would take several weeks and therefore using supercomputers seems an ideal option.
Based on CFD simulations results, we developed and implement a new type of nonlinear boundary condition for ESPRESO to simulate convective heat transfer enforced by the water-air fog, that is generated by the quench nozzle.