각종 송출 호오스의 구경 및 길이가 농용양수로의 소요동력에 미치는 영향

Influence of Flowing Velocity and Length of Delivery Hoses on Power Requirement of Agricultural pump.

The water delivery hose for agricultural pump is getting popular in rural areas in korea. Friction head loss, discharge, and power requirements were measured in various discharge for different material and diameter of hose to get basic data for economical use in agricultural pump. The results attained in this study were as follows ; 1. Friction head loss increased significantly as the velocity increased, and the difference of velocity between the different diameter of hose was bigger than that between materials, which was resulted in the increase of the friction head loss. 2. Friction head loss in the case of that the velocity with 2m/sec was constant was about 3.53 to 4.01 m/100m in the diameter 3" and about 2.30 to 3.10 m/100m in the diameter 4". Material A of diameter 3" showed the maximum value 8.4m/100m in Reynolds number $2.0\times10^5$, 4" got the minimum value 2.24m/100m, the difference between these values was bigger than 6m per 100 meters in the friction head loss. 3. Darcy-Weisbach formular with friction coefficient [f] calculated by Nikurades formular in the smooth pipe or with friction coefficient [f] calculated on the base of C value 125 in Hazen-Williams formular was available in friction head loss of the water discharger hose in rural areas. 4. Total head increased as friction head loss increased , meanwhile total discharge decreased, and 20 percents of energy was more saved in Material C 4″pipe than Material A 3″pipe in the view point from the discharge per unit power requirement, this phenomenon suggested that long distance pipe would be advantage in larger diameter pipe for save of energy. for save of energy.