Etude experimentale de l'ecoulement turbulent d'une suspension trajectoires et vitesses des particules transferts thermiques entre les deux phases

An experimental study of suspensions of 120 μ and 480 μ mean-diameter glass particles in turbulent air flow is presented. Particle trajectories were recorded photographically and local velocities were deduced. Trajectories were linear and velocity distributions were uniform. Heat transfer between solid and gas was studied, cold particles being introduced into a warm air flow. Heat transfer coefficients were calculated from mean air temperature measurements at different points along the tube. Theoretical analysis shows that the problem may be solved by means of a simplified one-dimensional model. This model is based on a drag coefficient, and a heat transfer coefficient between air and particles. Using heat transfer and drag coefficients for a single sphere in steady flow to calculate lengthwise variation of mean velocity and air temperature, good agreement is found with the experimental results.