I have a butterfly valve of DN 2500. The design head is 28 m WC. From this I calculated the upstream pressure to be 2.744 bar. Then I calculated the head loss in the valve using the equation k*v^2/ 2*g, which came out to be 0.0649m. Again from this, downstream head comes to be 28-0.0649, which is 27.9351m. Hence the downstream pressure becomes 2.739 bar. Thus the pressure drop is 0.0064 bar. Discharge for the flow was taken 11.07 m^3/sec.
Now my problem is when i calculated cavitation coefficient using Pu-Pv/Pu-Pd, it was 386 which i think is fairly high (Pv=0.042 bar at 30degC). So Help plz

Question

I have a butterfly valve of DN 2500. The design head is 28 m WC. From this I calculated the upstream pressure to be 2.744 bar. Then I calculated the head loss in the valve using the equation k*v^2/ 2*g, which came out to be 0.0649m. Again from this, downstream head comes to be 28-0.0649, which is 27.9351m. Hence the downstream pressure becomes 2.739 bar. Thus the pressure drop is 0.0064 bar. Discharge for the flow was taken 11.07 m^3/sec.
Now my problem is when i calculated cavitation coefficient using Pu-Pv/Pu-Pd, it was 386 which i think is fairly high (Pv=0.042 bar at 30degC). So Help plz