1、翻译部分 Method of branch ariflow for calculatinga complicated mine ventilation networksLIU ZE gong（刘泽功）（University of Science and Technology of China, Hefei 230026, China）Abstract The solutions widely used at present for calculating complicated mine ventilation networks taken are ones in which resistan
2、ce of the branches and characteristic parameters of the fans are as basic values. A new input data. But it is timE and-energy-consuming to obtain the branch resistance solution is developed in this paper in which the branch resistance values are obtained through measuring and evaluating the airflow
3、of the whole ventilation network. Theoretical analysis is made of the establishment of a linear equation series with branch resistance as unknown numbers, an equation series for which one, and only one, result of solutions exists. This solution is programmed in C language and passed on a personal co
4、mputer. The programmed solotion programmed proves of practical use, as demonstrated by specific examples. Being different from other solutions, the method takes the branch airflow and fan working points as basic input data, and the present solution is of greater advantage for calculating ventilation
5、 networks of mines in operationKeywords air resistance, measurements, calculation, computersIntroductionAt present the key problem of calculating complicated ventilation network methods widely used is that until the resistance value of n items of branches of the network graph G=（V,E） （V is the set o
6、f joint points, |V|=m，E is the set of the sides, |E|=n）are available （except the fixed airflow volume branohes），the accurate solutions can be obtained. Due to the difficulties of getting the precise values of tens, hundreds or even thousands of branches of a large scale network, this paper suggests
7、a new method based on the data of branch airflow and fan working point, that is airflow measuring method. And the corresponding solution program is also given. 1 Basic law and basic principle1.1 Basic law（1） Airflow resistance lawAccording to mine ventilation, the roadway airflow resistance law isWh
8、ere, h is pressure loss along the roadway, Pa; R is resistance of branch, kg/ m7; Q is volume flow rate, m3/s.（2） Joining point airflow volume balance law The following equation underlies any joint point of a networkWhere, i is serial numbers of the networks joint points（i=1, 2, 3,m）; j is serial nu
9、mbers of the networks branches （j=1, 2, 3,n）; Qj is volume flow rate in branch j , m3/s; aij is airflow direction function of branch j connecting with joint point i,airflow of branch j flows into joining point ibranch j doesnt connect with joining point iairflow of branch j flows from joining point
10、i（3） Mesh airflow presure banlance law Where,i is serial number of meshes （i=1,2,3,n-m+1）;j is serial numbers of mesh branches （j=1,2,3,n）; HFi is airflow resistance value of branch j, kg/m7; Qij is volume airflow rate in branch j, m3/s; bij is airflow direction function of branch j of mesh i,airflo
11、w direction of branch j of mesh i identify with meshbranch j doesnt belong to mesh iairflow direction of branch j of mesh i doestt identify with mesh1.2 Basic principle Take the directive net graph as Go=（Vo, Eo） （|Vo|=m, | E0|=n ） as basic network and known volume airflow rate Qi（0） （i=1, 2, 3,n） a
12、s basic data, the independent circuits can be selected and the linear equations with branch resistance as variables can be obtained equation （3） According to graph theory, the number of independent circuits of a directive net graph is r0 （r0=n-m+1）1.2 .So only graph G0 can t build n independent circ
13、uit equations. But an operating mine often adjust its ventilation system, sometimes not affecting mine functioning, the ventilation system can be adjusted manually fo solving the ventilation network. Take G0 as the basic network graph,after first airflow adjustment, G0 can be changed into G1=（V1，E1）
14、 （|V1|=m1，|E1|=n1），the branch airflow volumes are Qi（1） （ i=1, 2,3,n1） respectively, the number of independent circuit equations is r1 （ r1 =n1-m1+ 1），after second airflow adjustment, the network is G2=（V2，E2） （|Vk|=m2, | E2|=n2），branch airflow values are Qi（2） （i= 1, 2, 3,nk），the number of independ
15、ent circuit equations is r2 （ r2= n2-m2+ 1）,after k times of adjustment, the network is Gk=（Vk,Ek） （|Vk|=mk., |Ek|=nk），branch airflow volumes are Qik （i=1, 2, 3,n2），the number of circuit equations is rk （rk=nk-mk+ 1）. For basic network graph Go , among r1, r2,rk circuit equations have r1，r2,.,rk cor
16、responding circuit equations with adjustable branches, hence equations should be cut off from r （ r=r1+r2+ r3+.+ rk.） before building branch resistance circuit equations. And k should guarantee r-rn.In general, after 13 times of airflow adjustment of G0, the number of the built independent circuit equations can exceed n.2 The establishment o
