A CFD Based Comparative Study of Perforated Vehicular Seat Designs

Abstract

Automobiles of different kinds are commonly used by different populations around the world. Two wheelers, like motorcycles and mopeds are very commonly used by people for local transportation especially in developing countries like India. The major problems faced by motorcycle users are back pain, numbness, heat experienced on top of the seat, sweating due to seat design, etc. Seats which are commonly available in market comprise of a simple foam block covered with a synthetic or natural material (fabric/leather). Typically, these seats do not have provisions for ventilation, or any other system to control surface heating. In this work, two concepts were conceptualized and modelled for a two-dimensional feasibility study using computational fluid dynamics (CFD) techniques. Two-dimensional models of two concept seats were created and fluid flow analysis was conducted using ANSYS 18. After considering the velocity and temperature variations in the two models, the most suitable model was found for conducting a three dimensional model analysis.
After selecting the best concept, three dimensional model was developed which comprises of perforated seat attachment and perforated seat cover. Perforated seat attachment was developed with six different geometries and perforated seat cover with solid protrusions was developed with four different geometries. Geometry versus flow analysis was carried out for all models and best models from both perforated seat attachment and perforated seat cover with solid protrusions was selected by considering velocity and temperature variations.
A combination model of ventilated seat was developed by combining best geometries from perforated seat attachment and perforated seat cover with solid protrusions. CFD analysis was carried out in the combined model of ventilated seat and its behaviour to air flow considering heat input from human body was studied. From the results obtained the net change in temperature of the air was found to be 2 to 3 and net increase in velocity was found to be 4 to 5 times the inlet velocity. We propose that this temperature drop should help to increase comfort of riders. Therefore, by providing ventilation to motorcycle seats, long duration journeys should become more comfortable for motorcycle drivers.