Abstract: The remote water supply system for forest fire fighting is an important technical means for forest fire fighting. In order to study the water conveying effect of the system, theoretical analysis and experimental research on the hydraulic characteristics of polyurethane hose were carried out. The results show that the frictional resistance loss of polyurethane hose along the pipeline is related to Reynolds number (Re) and wall roughness (??). Its flow is generally in the turbulent region. In the smooth pipe turbulent region, the frictional coefficient λ is only related to Re. In the mixed friction region, λ is related to both Re and ?. In the rough pipe turbulent region, λ is only related to ?. Under the same flow rate, the smaller the diameter, the larger the Re, and the greater the frictional resistance loss, and the earlier the flow state enters the next interval. For the same section of pipeline, the lower the roughness, the smaller the λ，and when the roughness decreases by one order of magnitude, the hydraulic loss decreases by about 40%, which can greatly improve the water conveying efficiency. Through experiments, it is measured that the absolute equivalent roughness of the single-layer DN100 polyurethane hose selected by the system is about 0.3 mm. The pipeline characteristic curve of the 10 km remote water supply system is calculated based on this, which is basically consistent with the experimental results, verifying the scientific nature of the water supply system working under the design flow rate.

Key words: water supply system, polyurethane hose, hydraulic characteristics, frictional coefficient