Two types of forced air supply in the kitchen are taken up. One method is to supply air upwards from the vicinity of gas burner, and the other is to supply air downwards from the area around the cooking food. The capture efficiency of exhaust gas and short-circuit ratio of supply air are investigated through experiment. It is turned out that the proportion of air flow rate induced by forced supply to exhaust flow rate in the case of upward air supply and the semidiameter of curved flow line of supply air in the case of downward air supply are the decisive factors of the capture efficency and the short-circuit ratio.
