Measuring Methods About A Heavy Rain On The Basis Of The Principle Of Orifice Discharge

Rainstorm is one of the main meteorological disasters in China, the harm mainlyincludes flood and waterlogged disaster. Rainstorm is a kind of disastrous weather which hada bad impact,continuous rainfall especially rainstorm in an area will lead to urban waterlogging, crops have been flooded, flash floods, river overflowed, housing was grappling,transport and telecommunications disrupted and bring serious impact to the production andliving of people.In recent years, events of drowning people caused by rainstorm water loggingis more frequently,brought heavy losses of lives and property. Therefore, in order to providepowerful basis to the city construction and industrial and agriculturalproduction, the way of further improving measurement accuracy of storm rainfall is verynecessary.To meet diversified demand of rainfall monitoring, aiming at the defects of the structureof tipping-bucket rain gauge, this article studied the relationship between pressure andvelocity by experiment, established the mathematical model of the pressure and flow rate.Designed the rainfall measuring control process on the basic of principle of orifice discharge:when the internal water of rainfall monitoring system up to set height, valve was opened bymicrocomputer, water came out, rain gauge synchronous measurement of rainfall at the sametime, If the height of the water lower than set height, the valve closed automatically.So whenthe rainfall intensity is small, the valve dose not need to open, rainfall intensity is the outputof transmitter, its measurement error is less than1%FS.When the rainfall intensity is bigger,the valve need to open,but also avoid the measurement error caused by the loss of rain,theexperimental results show that the measurement error is less than8%FS.The characteristic ofthis design is there is not a flip structure, avoid the measurement error caused by the flipstructure. Implementation cost is low,can achieve the function of the automatic measurement of rainfall information, the measurement error will not change by the change of rainfallintensity, provides a new measurement method for rainstorm measurement.This rainstorm measuring methods can be used to measure the rainfall in differentregions,provide accurate information to the policymakers when they handle the problem ofurban water logging, landslide, debris flow, flood and reservoir management,reduce the losscaused by rainstorm disaster effectively.