Abstract: In order to clarify the relationship between baffle length of volute and radial force balance， the radial force of single volute pump and double volute pump with three different baffle length was studied in IH\|200\|150\|400 double volute pump at five different operation points based on CFD numerical simulation. The structure scheme of double volute was: L1，baffle radian 110°; L2，baffle radian 180°; L3，baffle radian 195°. The numerical simulation result indicated that double volute pump can effectively balance the radial force than single volute pump. With the increase of baffle length， the effect of radial force balance of double volute pump was improved， but the improving effect was not obvious. When baffle radian that around impeller was greater than 180°， baffle length had little influence on radial force balance. Its rational to take L3 as the baffle length considering the radial force balance and casting difficulty. Compared to the single volute pump， double volute pump had a lower efficiency and pump head. With the increase of baffle length， the efficiency showed an increase trend yet the head showed a decrease trend.

Key words: double volute pump, baffle length, radial force balance, numerical simulation, static pressure distribution