Research On Limit Value Of Failure-free Operating Probability Index Based On Model Heat Network

With the rapid development of heating systems,China's centralized heating pipe network has become more and more large,but large-scale heating pipe network brings convenience to people's lives,but also accompanied by many accidents.Not conducive to people's comfortable and safe life.At the same time,the repair after the failure of the pipe network also consumes a lot of manpower,material and financial resources,which is not conducive to economics.Therefore,research on the reliability of central heating systems is very necessary.For domestic and foreign scholars,relevant research has been carried out on the reliability of heating systems.However,in the field of heating reliability,there are few studies in China,and Russian regulations and data are used in research.In this paper,by arranging the statistics of some urban faults in China,the average pipeline fault flow parameters and valve fault flow parameter point estimation values and interval estimation values in different cities and China are calculated,and the relationship between component fault flow parameters and pipe diameter is analyzed.Calculate the pipeline fault flow parameters and valve fault flow parameter data that can be used for the calculation of reliability index in China based on the heat network model established in this paper.By consulting the domestic and foreign literatures,the allowable temperature drop of the room temperature,the average repair time of the component accidents,and the heat storage coefficient of the heat user buildings under the heating conditions of the heating pipe network are determined.The calculation of the indoor minimum temperature is 10 according to China's national conditions.Limit of heating coefficient at °C and 12 °C.By establishing a common single heat source branch pipe network model,a single heat source ring pipe network model,and a long distance pipeline network model,the reliability index of the heat network model is calculated,and the reliability index R and pipeline under different pipe network models are analyzed.The relationship between length,number of pipe network valves,pipeline fault flow parameters,valve fault flow parameters,comparative analysis of the relationship between reliability index and Russian reliability index of different pipe network models under the same conditions,calculation based on the heat established in this paper China's reliability index limits for net models.Through related calculations and analysis,this paper proposes the pipeline fault flow parameters,valve fault flow parameters and the indoor allowable minimum temperature 10 ° C and 12 ° C limit heating coefficient limit for the calculation of reliability index in China;Based on the reliability design theory,it is concluded that for the longdistance pipeline,it is not appropriate to adopt two forms of control,and the conclusion should be adopted in the form of multi-control(three-control or four-control);The reliability index calculation and analysis of the heat network model is proposed,and the reliability index limits of China based on 16 models are proposed.