Operating conditions of a mine fan under conditions of variable resistance

Transcription

1 Paper No. 11 ISMS 216 Operatng condtons of a mne fan under condtons of varable resstance Zhang Ynghua a, Chen L a, b, Huang Zhan a, *, Gao Yukun a a State Key Laboratory of Hgh-Effcent Mnng and Safety of Metal Mnes (Unversty of Scence and Technology Beng, Mnstry of Educaton, Beng, 18, Chna b College of resources, Hebe Unversty of Engneerng, Handan, 568, Chna ABSTRACT Accordng to the basc flud prncples and ventlaton laws combned wth the ventlaton network computng method, ths study proposes the concepts of relatve senstvty and absolute senstvty, and studes these two senstvtes varaton law under condtons of varable arway resstance. The result showed that when the arway resstance ncreased, the fan ar volume, relatve senstvty, absolute senstvty and fan pressure s relatve and absolute senstvty tend to decrease. At the same tme, fan pressure shows an ncreasng trend. Conversely, when the arway resstance goes down, the above parameters follow the opposte trend. These results provde a bass and gudance for adustng the fan operaton condton n the mne producton process. KEYWORDS: varable resstance, operatng condtons, change rule, senstvty 1. INTRODUCTION Mne Ventlaton System s one of the basc producton systems that ensures the safety of underground work personnel lfe (Zhou et al., 25. In recent years, the mnng strength, depth, and the producton level have all been ncreasng, whch leads to ncreasngly complex ventlaton systems and exstng dagonal structures n the mne ventlaton system, whch make the ventlaton management ncreasngly dffcult. The actual producton process needs tmely adustment of volume, because the workng face to replace, wnd resstance of roadways, the network structure and the need to ar volume are constantly changng (M, 29. Ar condtonng s a dynamc process, and the nonlnear changes not only ncrease the dffculty of ar volume adustment for complex ventlaton networks, but also have a sgnfcant mpact on producton safety. Therefore, masterng the complex network ar regulaton change rules requres more and more attenton. Zhou (1995 put forward and llustrated the smple calculaton method of the adustable resstance value, based on the nfluence of the network. Zhao et al. (2 developed measures of ncreasng anecreasng the resstance to adust the ar volume on the ndvdual ventlaton networks. Zhou et al. (25 analyzed the senstvty of the branch arflow to the wnd resstance and the natural wnd pressure, n order to udge the stablty of ventlaton networks. Jao et al. (29 analyzed the partal ventlator regulatng ablty and ntroduced the concept of ar volume adustable tunnellng faces. Wu, (211 used the senstvty to quantfy the selecton crtera of the ar regulaton pont. Yan et al. (211 studed the ventlaton system ar volume and wnd resstance changes between the superpostons. Hu et al. (214 explored the complexty of mne ventlaton network and fan control. There are few reports on ar regulaton change law for complex ventlaton network. The present study examnes the fan ar volume and ar pressure change rules and regulaton of senstvty for the man branches of the complex ventlaton network system, n order to provde a bass and gudance for mne ar regulaton. 2. MODEL OF THE VENTILATION NETWORK SYSTEM The set of the ventlaton network nodes s J = ( 1, 2,, m where m s the number of nodes. The set of the ventlaton network branches s E = ( e1, e2,, e n, where n s the number of branches. The ventlaton network can be expressed as G = ( V, E A typcal complex ventlaton network that ncluded seres, parallel, and angle type and contanng eght nodes and twelve branches was bult, as shown n Fgure 1. *Correspondng author emal: huang_za@qq.com

2 The wnd resstance nformaton of each branch was as shown n Table 1. The basc nformaton of the fan was as shown n Table 2. Fgure 1: The ventlaton network. The wnd resstance change of branch s defned as the varable resstance branch. When the varable resstance branch of wnd resstance changes the ar flow and pressure of the fan, ths magntude of the ar volume change s defned as the senstvty of ar volume for varable resstance, called. The rato of the ar flow (pressure varaton and the wnd resstance of varable resstance branch s defned as the absolute senstvty, called ψ. The formulas are as follows: ( Q ( R ( Q Q ( R R q = = (1 ( Q d( Q Q d q = = (2 R R ( H ( R ( H H ( R R f = = ( ( H d( H H d f = = (4 R R Where: Q s the fan branch ar volume after varable resstance of the tme measured n m / s ; H s the fan branch of wnd pressure after varable resstance of the tme; Pa ; Q s the fan branch ar volume ar volume after varable resstance of the 1tme measured n m / s ; H s the fan branch of wnd pressure after varable resstance of the 1 tme; Pa ; R s the resstance value of the varable resstance branch after the tme varable resstance; R s the resstance value of the varable resstance branch after the 1 tme varable 8 resstance measured n N. s 2 / m. Table 1: The value of the each branch wnd resstance. Branch number Value of the wnd resstance (N. s 2 /m 8 e 1. 1 e e. 5 e e e e e e e 1. 2 e e Table 2: The basc nformaton of the fan. Fan model FBCDZ-6-2 Wnd pressure( Pa Ar volume (m /s Motor model YBF 2-15S-8 Rated speed (r/mn 9 Rated power (kw VENTILATION NETWORK SOLUTION Network soluton s one of the mportant ways to adust and analyze the ventlaton network. Ths s theoretcally based on the three laws of ventlaton, whch are the ar volume balance law, the mesh ar pressure balance law, and the law of resstance (Zhang, 2. (1 The balance law of ar volume: The mass flow of each branch that nflows and outflows of a node algebrac addton s zero. The formula s as follows: M = (5 (2 The balance law of the mesh ar pressure: In a closed loop wthout a power source, the ventlaton resstance of the branches algebrac addton s zero, whle wth a power source, the ventlaton resstance of the branches algebrac addton s equal to fan ar pressure of the loop. The formula s as follows: h = or h = hf (6 ( The law of the resstance: The resstance of the roadway s equal to the product of the wnd resstance and ar flow square. The formula s as follows: 2 h = RQ (7 44

3 By combnng (5 to (7, the ar volume was calculated usng the Scot-Hnsley algorthm. The network solver s wrtten usng the VB. net platform. 4. THE DISCUSSION AND ANALYSIS e 8 and e 9 were selected as a branch of varable resstance, whch are parallel branches. e 8 s the ncreased resstance branch, whle e 9 s the reduced resstance branch, resstance changed 2 tmes n successon, and the network was calculated once the resstance changed. The computed results are as shown n Table. Table : The computed results Adustment tmes ( Value of the ncreased resstance 2 8 N. s / m Pressure of the fan( Pa The ar volume of the fan ( m / s Adustm ent tmes Value of the reduced resstance ( N. s 2 / m 8 Pressure of the fan( Pa Ar volume of fan( m / s The change rule of the fan ar volume and ar pressure When the arway resstance changed, the fan ar volume and ar pressure changed, as shown n Fgures 2 and. The fgure shows that, when the arway resstance ncreases, the fan pressure wll ncrease and the fan ar volume wll decrease; On the contrary, when the arway resstance decreases, those parameters change follows the opposte trend. Ths s due to the changes of total wnd resstance n the ventlaton network system caused by the arway resstance. Fgure 2: The changed curve of the fan ar volume when varable resstance. Fgure : The changed curve of the fan pressure when varable resstance. 4.2 The senstvty of the fan ar volume and ar pressure The computed results were substtuted nto formulas (1 to (4. The relatve and absolute 444

4 senstvty of the fan ar volume and ar pressure were computed when varyng the resstance, as shown n Fgures 4 to 7. The fgures show that, when the arway resstance ncreases, the relatve and absolute senstvty of the fan ar volume and ar pressure showed a decreasng trend. The curve s ntally steep before gradually slowng. When the arway resstance goes down, the relatve and absolute senstvty of the fan ar volume and ar pressure showed an ncreasng trend, wth the relatve senstvty stablty ncreased gradually. The early stage of the absolute senstvty changes smoothly, whle the late stage ncreases suddenly. Ths suggests that the nfluence of the fan ar volume and ar pressure s obvous when the arway resstance ncreases n the early stage and the arway resstance goes down n the later stage. Fgure 6: The senstvty curve of the fan ar volume when ncreased resstance. Fgure 4: The senstvty curve of the fan pressure when ncreased resstance. Fgure 5: The senstvty curve of the fan pressure when reduced resstance. Fgure 7: The senstvty curve of the fan ar volume when reduced resstance. 5. CONCLUSIONS The followng conclusons can be drawn: Frst, when the arway resstance ncreases, the fan ar volume, ts relatve and absolute senstvty, and fan pressure s relatve and absolute senstvty, tend to decrease. At the same tme, fan pressure showed an ncreasng trend. Conversely, when the arway resstance goes down, the above parameters change n the opposte drecton. Second, the nfluences of the fan ar volume and ar pressure s obvous when the arway resstance ncreases early on, and then gradually weakens. Conversely, when the arway resstance goes down, the nfluence of the fan ar volume and ar pressure follow the opposte trend. These results provde a bass and gudance for adustng the fan ar volume n mnes. Fnally, when ncreasng the resstance, even the appearance of the fan ar pressure beng too hgh should be avoded, as t could cause unstable runnng of the fan, and ultmately mpact safe producton. 445

5 6. ACKNOWLEDGEMENT It s wth great pleasure that we acknowledge the generous fnancal support of Natonal Natural Scence Foundaton of Chna (proect number: and Natural Scence Foundaton of Xnang Uygur Autonomous Regon of Chna (214211B1. 7. REFERENCES Hu, H. H., Yang, G. Z. (214. Quantfed calculaton on complexty of mne ventlaton network and control force from man ventlator. Journal of Safety Scence and Technology, Volume1, No. 7, pp Jao, Y., Zhou, X. Q., Gong, W. (29. Network analyss of ar volume adustment n mne tunnellng faces durng the perod of the normal producton. Mnng Safety & Envronmental Protecton, Volume 6, No. 6, pp M, X. K. (29. Mne local ar volume and total ar volume adustment. Coal Technology, Volume 28, No. 5, pp Wu, F. L. (211. Usng senstvty to optmze mne ar regulaton pont and parameter. Mnng Safety & Envronmental Protecton, Volume8, No. 5, pp. 1- Yan, Z. G., Fan, J. D., Wang, H. (211. Superposton features of ar flow's changes n a mne ventlaton system. Scence & Technology Revew,Volume29, No. 4, pp. 7-4 Zhang, G. S. (2. Ventlaton Safety. Chna Unversty of Mnng and Technology Press, 85-92p Zhao, D., Lu, W. H., Yao, L. Z. (2. Calculaton and Regulaton of the Local Ar Volume n Mne. COAL, Volume 12, No., pp. 5-6 Zhou, J., Lu, J. and Ja, J. Z. (25. Analyss senstvty of mne ventlaton system. Journal of Laonng Techncal Unversty, Volume 24, No. 4, pp. 1- Zhou, L. H. (1995. Calculaton and analyss of the ar condton n mne ventlaton network. J. XIANGTAN MIN. INST, Volume1, No. 4, pp