1、 l : 1999- 03- 25 Te:S?, 3, 1963 M 3, q1 cI| 1006- 0456( 2000) 02- 0072- 05 5 1 D 19 T 周国发 李鸣 屈娅嘉 (南昌大学环境与化学工程学院,江西南昌 330029) K1 D 1s$ ,4 B D 19 T1 D 11 s 5 1D E Y, 5 1 V D 11D E Vv, DB) 1 1oM D, 1,9 T mEs | TQ 0511302 DS M A 1 - D K1B ,W PV !5Z , 9 D D,i V L1G 1SSESGB150- 895 6, D ,4 9 T1N, D ) , 9
2、 T -41 - D 1 i 4: 1)S?S ( D 1 5 1M, 0. 52811, 2212)7E , D 1l 5 1, 0. 2 0. 31321 , O D 1 9 ZE,yN, D 1i D , Bs %513YV s k,) D ,4 D 1 9 T1B - nD1 2 D 15s 1rcr Kl ), r H g 11 5 1 V T9 1 5 g 1 5 1 H, g X , g 1 ?V ,N ?Y 5 = 1 g p 2/ p 1= rcrM, g ,M 9M,W/ W max= 11N H, 5) 1421 5, 11 k ,7 k 1= 1, uY1 D, 4 D
3、Kl ) ,V7E K 22 2 2000 M6 2v( S) Journal of Nanchang University( Engineering , M W/ W maxM, g X , D) ,5 C G k 1 m1 Dem m1 Dem,C DD = 5 T1D = 5 gD#D 8T PYV 8 3BE $p,CE $p 9DD 8T,5V 4 A, D Vem2 U9 ,m pb D g 1 D g p 1 9F,DE $p 9F, PD = 5 g p299F,T V ? Pp 2p19 ,D = 5 1r = p2/ p 11 5 9 T V,N H 5 v ,K P D
4、1M lM1 m2 9 ii DKl ) 8 r ,A , H 1iB T D 11,D 7 l H, D . 1r0. 67 H, 7 S 1 M1 , 1 ? D 1,yV , D 1 V ?1 5 1v1 m2 V, D X 5B uYQDE $p 1?S.d 9 ZE ( X 59 ,7 DE T, | D 5Mj, B) T P p D 1 5M, ( 01528, D 5 A uY,4A 1 3 D 19 D X 51sQDE ,7.dZE9 I nDE $pT, 1m2 U 9 Q D 51s,D = 5 g p2 p 2= pb+ $p (1) T$p= f Q2v 22 2
5、(2) #73#2 S?: 5 1 D 19 T o pQ1v 1A 1= Q2v 2A 2 v 2/ v 1= Q1A 1/ Q2A 2 (3) , ? o p dh+ d(v 2/ 2) + gdz = 0 (4) T: Q1, v 1, Q2, v 2sYD = 5a g) 8 ;fDqE ; h 1; z1 X 8 dh= cp dT (5) Ocp M,i gdz(gdz 0),5(4) T(5) Ts cp(T 2- T 1) + (v 22- v 21)/ 2= 0 (6) cp = kR0/(k- 1) (7) T 2/ T 1= (p2/ p 1)(k- 1)/ k (8)
6、(2),(6),(7),(8) T v 2= 2kR0T 1 k- 1 ( r k- 1k - 1) (A 2A 1 )2r 2k - 1 (9) T: v 2 V U 5 152; k ; A 1, A 2sYD = 5a g ) ; R0 8 ; T 1 g; rD = 5 g 1, r= p 2/ p 11 C| T(1) Hp 1,i| T(2) T( 9) e, Vw D 1 D = 5 11 T r = rb+ fkk- 1# r - r 1 k ( A 2A 1 )2#r 2k - 1 (10) T: rb D 1, rb= pb/ p11 T D 5,yN D ? 5 r1D
7、= 5r H, D) , T( 10) V, D 1rbcrD = 5 1rcr1 T rcr = rbcr + fkk- 1# rcr - r 1 k cr (A 2A 1)2#r 2 k cr- 1 (11) 7 V U p 5 1rcrZ T152 (k- 1)( A 2A 1 ) 2#r 2 k cr + 2r 1- k k cr - (1- k)= 0 (12) |(12) T ( 11) T, Vw D 19 T rbcr = (1- fk2 )#rcr (13) #74# 2v( S) 2000 M b , 5 1, rcr = 0. 528,1YV LE f , V T9 D
8、11 4 Ts) T(13) V, D 1rbcr1 s 5 1rcrD E f Y1D E f9F H, 5 1 ,5 D 1|hl1 N Vn, D 1 D E 9F7hl1 E 9F B H,5 D 1|hl01 TDE V ,D E Vv, DEr ,7 ) 1 1 Di , 5 D 1l0,rbcr 0,N HD E f f 2/ k1 b , k= 1. 4, f 1. 431N Vn, D ) , D E f ?V1. 431 D ) ,3A42Y - 1. 6C DN40 A42Y- 1. 6C DN50 DD E k k1m3D E D 1 k1 wL, :US USV U
9、E 1 kTV , T DD E (V1. 431 V, P D g v, D (D E Vv,7r ,yN, DB) 1 ( a) A42Y- 1. 6C DN40 D ( b) A42Y- 1. 6C DN50 D m3 D E D 1 k1 wL h ) 7 ;y ) L 7 m4 D 1D = 5 1 L wL w V L,3 D 1# D = 5 1 k k, D 1 D = 5 1 k kTnm41 k TV , D g r016 M Pa(V) H, D = 5 1 (V0171N Vn,D = 5 ) 17 T D 5, D ? 5r 1yN, D = 5r H, D) 1 8
10、 ,DE Vv,D = 5) ,N V, T DDE #75#2 S?: 5 1 D 19 T Vv,7 P DB) 1w kT 1.d4 , D g r016 M Pa(V) H, D) , kT ,yN,C.dZE D Z iB51 5 1) D 51 uYDE , I nDE T , | D 5Mj1 2) D 1 D E 9F7hl1 3)DE Vv, DB) 1 ID 112 S S1 GB150- 89 1S21: , 19891 122 ASM E1Q V# s ?S:s 1S21 U. S. A, New York, 19951 90 941 132 B T 51 D1M21;
11、r1 Z: Z S/ , 19821 1 801 142 1 8 $1M21:S , 198911 2051 152 S?, n b,61 D s1J21 , 1997, ( 2) : 4 81 TheFormulaof theCritical PressureRatioforSafetyValve bytheCritical PressureRatioforNozzle Zhou Guofa Li M ing Qu Yajia (Environmental and Chemical Engineering School, Nanchang University, Nanchang 33002
12、9, China) ABSTRACT T he form ula of the critical pressure ratio for safety valve is proposed. The experiment results show that the critical pressure ratio for safety valve is affected by the critical pressure ratio for nozzle and the resistance coefficient for valve disc, safety valve is alw ays in sub- critical flow state because the resistance coefficient of valve disc is greater. KEYWORDS safety valve, critical pressure ratio, formula #76# 2v( S) 2000 M
