Window purifying ventilator using a cross-flow fan: Simulation and optimization

The window purifying ventilator is a relatively new idea that involves replacing one part of the window frame with a ventilator, for which the core component is a cross-flow fan (CFF). When a CFF is applied to the window purifying ventilator, a filter should be added, and its casing should be modified. In this paper, first, time-accurate solutions with a sliding mesh technique were developed for modelling the two-dimensional viscous and incompressible model of CFF. Three prevalent two-equation turbulence models (Standard, RNG and Realizable k-ε models) for CFF simulation were compared and validated in the experiments, and the most suitable model for this type CFF was found. Based on the time-accurate simulation, the formation of flow construction inside the CFF was also observed and explained. Next, the CFF was optimized for window purifying ventilator by redesigning and modifying the shape and location of vortex wall and rear wall, both numerically and experimentally. From the research results, the vortex wall’s position has a great influence on the ventilator’s performance by determining the position and intensity of eccentric vortex, and the shape of the rear wall also affects the ventilator’s performance by determining the flow pattern and internal flow resistance. Through appropriate designing the vortex and rear wall, finally, the CFF could apply to the window purifying ventilator with acceptable flow rates.