Static In-Line Gas Mixer for Physiological Capnogram Simulation

For the simulation of a physiological capnogram with a lung simulator it is important to homogenize CO2 in the expiratory air adequately with a mixing element, while being limited in size and energy consumption. We design and test static in-line mixers based on helical blade (Kenics) design and crossbars (SMX) design for optimized homogenization of CO2 in air. We investigate the effect of design variations such as element length and number on gas homogenization and pressure loss coefficient ζ. With the chosen assessment method, we find that the SMX design mixer provides the best compromise between homogenization and pressure loss.