PRACTICAL EXPERIENCE WITH THE INTRODUCTION OF HONEYCOMB SHROUD SEALS ON MW SUPERCRITICAL PRESSURE UNITS

Transcription

1 Power Technology nd Engineering Vol. 7, No. 6, Mrch, 0 PRACTICAL EXPERIENCE WITH THE INTRODUCTION OF HONEYCOMB SHROUD SEALS ON MW SUPERCRITICAL PRESSURE UNITS A. S. Lisynskii, V. G. Griin, Yu. A. Skhnin, O. V. Ft'kov, K. V. Gorlitsyn, 5 nd S. V. Ushinin 5 Trnslted from Élektricheskie Stntsii, No. 0, Octoer 0, pp. 8. Prcticl experience with the introduction of honeycom sels in the flow-through sections of MW stem turines with supercriticl stem pressure is exmined. The most widespred designs for shroud nd end honeycom sels used in the development of new turine units re discussed, long with the moderniztion of existing stem turine equipment. Test stnd dt on the reltive flow rte nd power chrcteristics of honeycom, rdil, nd xil-rdil sels re compred. Results re reported from therml tests for evluting the efficiency of instlling honeycom shroud sels in the high pressure cylinders of the T turine units t the TÉTs- plnt of JSC Mosénergo nd the K turine units t the Perm GRÉS plnt of JSC OGK-. Keywords: honeycom sel; stem turine; turine unit; efficiency; flow-through section; therml tests; supercriticl pressure; flow rte nd power chrcteristics; low-frequency virtion. One of the tsks in improving the therml-mechnicl nd opertionl performnce of existing stem turine equipment is moderniztion of the flow-through sections using improved designs for sels with honeycom surfce. The reltive internl efficiency of the high pressure cylinder hs een incresed y 0.6.7%, just y reducing the rdil gps during instlltion of honeycom shroud sels, with the mximum increse ttined when ll stges of the cylinder re equipped, including the regultor. Design of honeycom sels used in modernizing the flow-through sections of MW stem turines. Over the lst decde the firm ARMS (Moscow), together with the mnufcturers of stem turines JSC Power Mchines (St. Petersurg) nd JSC UTZ (Yekterinurg) hve used the production fcilities of JSC NPP Motor (Uf) to develop nd introduce honeycom shroud nd end sels for MW turine units. Some of the sic designs for honeycom sels currently in use in the flow-through sections of turine units with supercriticl stem pressure re shown in Fig.. Sels of the types shown in Fig. nd d, re instlled on more thn 70 stem turines of types T-00-0, K-00-0, PT-60-0, nd PT-80-0 nd modifictions of these. JSC Power Mchines, LMZ, St. Petersurg, Russi. Ntionl Reserch University Moscow Power Engineering Institute, Moscow, Russi. JSC Urls Turine Works, Yekterinurg, Russi. JSC SCPE, Moscow rnch, Moscow, Russi. 5 NPP ARMS, Moscow, Russi. In order to increse the reliility nd optimize the honeycom sel design, JSC Power Mchines, NPP ARMS, nd NRU MPEI hve crried out test stnd studies of wer in sel components (rotor collr nd honeycom ssemlies with cell dimeters of 0.9,., nd.5 mm) in mutul contct. The tests were done in vrious rottionl modes ( 600 rpm) with mximum incision depth of.0 in the honeycom surfce. An nlysis of the dt shows tht the honeycom ssemlies with cell dimeters of mm nd wll thicknesses of 0.05 mm re quite soft nd esily cut during contct, while the rotor collrs undergo miniml rsion without signs of heting (no temper color). No removl or flking of the honeycom surfce ws oserved fter the tests. Honeycoms with cell sizes of.5 mm were chosen s preferle for reking in the honeycom surfce for further use in the flow-through sections of stem turines. Figure shows some pictures of the yoke of the regultor stge of the high pressure cylinder nd the diphrgm of the medium pressure cylinder of K-00-0 turine unit in which the most typicl wer of the honeycom nd trditionl rdil sels cn e seen. During initil strtup of one of the turine units s it ws eing overhuled, incresed virtion of the high nd medium pressure rotors (unssocited with the instlltion of honeycom sels) up to levels of. mm sec ws detected. An inspection of the shroud sels of the flow-through section of the high pressure cylinder reveled the presence of contct wer of the honeycom surfce y up to mmintherdil direction nd mm X Springer Science + Business Medi New York

2 Introduction of Honeycom Shroud Sels on MW Supercriticl Pressure Units Gp 0.5 mm 5 7 Gp.5 mm Overlp.5 mm Gp 0.5 mm Gp6mm Gpmm Overlp 0.8 mm Gp. mm Gp.5 mm 9 Gp.5 mm Overlp.5 mm 5 8 Gp 0.5 mm 6 Gp0.5mm Gp. mm Gp. mm 9 c Fig.. Honeycom shroud sels for the high nd medium pressure cylinders of T (), K-00-0 nd K ( ), K-00-0, K-0-0MR, nd K (c) turine units nd for the medium pressure cylinder TsSD- nd the low pressure cylinders of T turine (d ):, rotor lde;, rotor collr;, honeycom ssemly;, pin; 5, honeycom insert; 6, yoke; 7, diphrgm; 8, director lde; 9, lde shroud; 0, rotor ushing;, segment of honeycom end sel. d Fig.. A honeycom shroud sel for the flow-through section of the high pressure cylinder () nd rdil shroud sel for the flowthrough section of the medium pressure cylinder (c) of K-00-0 turine unit fter contct wer:, yoke of regultor stge;, honeycom ssemly;, honeycom sel;, depletion of honeycom surfce; 5, shroud collr; 6, diphrgm; 7, sttor collr (00% wer); 8, lde shroud. xilly. No wer ws oserved in the rotor shroud collrs t the time. In this sme cse, complete rsion of the sel collrs of the trditionl flow-through sels locted t the diphrgm of the medium pressure cylinder ws oserved. Figure shows the honeycom end sels of the low pressure cylinder of T turine unit fter 5 yers of 8 Fig.. Honeycom end sel of the low pressure cylinder of T turine unit fter 5 yers of opertion:, yoke;, sel segment;, rotor collr;, wer of honeycom surfce. opertion. The honeycom surfce ws worn rdilly y up to.0.5 mm nd xilly y up to.5.0 mm. There ws no temper color. The wer of the honeycom surfce in the xil direction corresponds to the reltive displcements of the rotor. The stte of the honeycom surfce ws found to e stisfctory upon inspection nd the sel ws pproved for further use without replcement nd repir []. Operting experience with T turine units in the JSC Mosénergo system [] lso confirms the effectiveness of using honeycom end sels for the medium pressure cylinder TsSD- nd the low pressure cylinder: the opertion of the ejectors ecme norml nd the mount of wter in the oil ws reduced, nd the rnge of reltive displcements of the medium pressure rotor RSD- ws expnded.

3 A. S. Lisynskii et l. ä =.9 mm Version Version ä = vr ä =.5 mm ä =.9mm Version Version ä =vr ä = 0.9 (.5) mm ä = 0.9 (.5) mm G D G D.0.0 ä =0.9mm ä =0.9mm ä Ä Fig.. Plots of the rtios of the flow rte G () nd power D (c) chrcteristics of honeycom nd rdil sels: ä, the gp in the sel; D = mm, the collr thickness ä =.5mm ää ää Fig. 5. Plots of the rtios of the flow rte G () nd power D (c) chrcteristics of honeycom nd xil-rdil sels: nottion s in Fig.. Wer of the honeycom surfce generlly occurs during trnsitionl modes of opertion of turine unit (cold strtup, psses through criticl frequencies of the shft line, stopping, etc.), when the sel components of the flowthrough section occupy n intermedite position reltive to one nother. During stedy-stte opertion of the turine the rotor collrs occupy their working position (which differs from the intermedite position) ove prt of the honeycom surfce with no wer. The flow of stem through the honeycom sels essentilly does not increse, nd oth the shroud nd end sels continue to operte efficiently with the minimum permissile gps. Bsed on lrge mount of sttisticl dt otined during inspection of the flow-through sections of stem turines, technicl specifictions hve een developed for the use of operting personnel t power plnts nd in greement with JSC Power Mchines nd JSC UTZ for evluting the stte of shroud, diphrgm, nd end honeycom sels which estlish the order of fult detection, tolernce criteri for further opertion, nd, when necessry, the mount nd type of repir nd recovery mesures to e undertken during mjor overhul of turine units. Results of the test stnd studies. In order to optimize the geometric dimensions of the honeycom cells nd determine the minimum permissile gps in the shroud sels of the flow-through sections of supercriticl pressure turine units tests were mde on the stnds t the A. V. Shcheglev Dept. of Stem nd Gs Turines t the Moscow Power Engineering Institute together with JSC Power Mchines nd NPP ARMS to study the power nd flow-rte performnce of honeycom, rdil, nd xil-rdil shroud sels tht were identicl in terms of their geometricl chrcteristics to those used in the flow-through sections of stem turines [, ]. For correct comprison, ll the dt were reduced to unified initil flow prmeters (initil pressure hed of the sels P 0 = kp, temperture hed of the sels t 0 = C, tngentil component of the flow velocity t the sel inlet C 0 =m sec, rtio of the pressure fter the sel to tht efore the sel å = 0.806). The plots in Fig. of the reltive (to the clculted vlue) flow rte G nd reltive rigidity D of the nonconservtive erodynmic force were otined for ä vr. = vr nd ä vr. = const =.5 mm, where version is identicl to the honeycom shroud sel for the high pressure cylinder of T- 00-0, PT-60-0, K-00-0, K-00-0, nd K turines nd version corresponds to the rdil sels trditionlly used in the high pressure cylinders of PT-60-0, R-50-0, nd K-00-0 turines. An nlysis of the curves in Fig. shows tht the flow G through honeycom sel with working gp of ä = 0.5 mm is 0% of the flow through rdil sel with working gp of.5 mm. The rigidity of the erodynmic nonconservtive force D of the honeycom sel for gps smller thn 0.5 mm hs tendency to fll off rpidly compred to the rigidity of flow-through sel with rdil gp of ä =.5 mm. The plots of reltive flow rte G nd reltive rigidity D for the nonconservtive erodynmic force shown in Fig. 5 were otined for ä vr. = vr nd ä vr. = const = 0.9 (.5) mm (two xil-rdil sels with gps over the selnt surfce of 0.9 nd.5 mm were studied). Here version is identicl to the shroud xil-rdil sels employed in the high pressure cylinders of T-00-0, K-00-0, nd T-50-0 turines. The flow through the honeycom sel with working gp of ä = 0.5 mm is essentilly equl to the flow through n xil-rdil sel with working rdil gp of 0.9 mm; here the rigidity of the nonconservtive component of the erodynmic force for the honeycom sel is lower y 0 5% thn tht for the xil-rdil sel. The flow through the

4 Introduction of Honeycom Shroud Sels on MW Supercriticl Pressure Units í r, í s ä Fig. 6. Prmeters of the vortex on the sttor (v s ) nd rotor (v r ) surfce of the sels:,, v r nd v s for honeycom sel, respectively;,, v r nd v s for sel with smooth wlls, respectively; d, the gp in the sel; = 5 mm, the height of the sel chmer. honeycom sel with working gp of ä = 0.5 mm is 0% of tht through n xil-rdil sel with gp of.5 mm. During the experiments pneumometric proe ws used to mesure the velocity nd direction of the flow in the shroud chmer t the oundries of the sttor nd rotor. A comprison of the vortex prmeters (v r, v s ) yields the following conclusion: in the honeycom sel the vortex intensity is sustntilly lower thn in sel with smooth wlls for the shroud chmer. Under some operting conditions the reduction ws up to 0%. For smll rdil gps (ä 0.5 mm) ner chnnel flow developed in the chmer. A reduction in the difference etween the solute vlues of v r nd v s in the honeycom sels ws detected over the entire rnge of reltive gps compred to sels with smooth wll (Fig. 6). It ppers tht the incresed roughness of the honeycom surfce cuses considerle reduction in the tngentil component of the flow in the shroud chmer (ids in quenching the vortex) nd, therefore, reduces the nonconservtive component of the erodynmic force, therey confirming tht using honeycom surfce in shroud sel is not the destilizing fctor tht fcilittes the development of low-frequency virtion of the rotor []. Results of therml tests of T unit t JSC Mosénergo. In the 970's during industril introduction of the type T-50-0 turine t Mosénergo it ws found tht low-frequency virtion of the high pressure rotor developed s the turine reched its threshold power [5]. This ws eliminted fter instlling virtion resistnt xilrdil shroud sels with rdil gps of mm long the sel surfce tht hd een proposed y JSC UTZ. Operting experience with honeycom sels on vrious types of stem turines [6] including supercriticl stem systems with rective lding (K-0-0MR, K-660-0), together with n nlysis of the experimentl dt hve mde it possile for experts t NPP ARMS to develop nd gree with JSC UTZ design for honeycom shroud sels for high pressure cylinders with rdil gps of mm. ç o i Reduced fresh stem flow, tons h Fig. 7. The vrition in the internl reltive efficiency of the high pressure cylinder of the T turine t unit No. 8 of the TÉTs- plnt of JSC Mosénergo efore nd fter instlltion of honeycom shroud sels:,, operting with the high pressure preheter turned off nd on, respectively (first stge of the tests);,, operting with the high pressure preheter turned off nd on, respectively (second stge of the tests); the flow rte is reduced to the nominl fresh stem pressure (.5 MP) nd temperture (50 C). The design solutions shown in Fig. hve een instlled in stges of the high pressure cylinders of four T turines: units No. 8 nd 9 t the TÉTs- plnt, unit No. t the TÉTs-6 plnt, nd unit No. 6 of the TÉTs-5 plnt, ll of JSC Mosénergo. The work ws done y the power plnt overhul compny TÉR-Moskv. Besides the honeycom shroud sels for the high pressure cylinders, in order to improve the mneuverility of the ove listed turines nd to prevent suction into the vcuum system, honeycom end sels hve een instlled in the collrs of the medium pressure cylinder TsSD- nd the high pressure cylinder with gps over the seling surfce of mm. To crete dditionl expnsion chmers nd eliminte therml ftigue of the surfce lyer of the metl, the fitting ushings of the rotors were ored out on the recommendtion of JSC UTZ (Fig. d ). Experts from the Moscow rnch of JSC Southern Power Engineering Center hve crried out therml tests to evlute the efficiency of introducing honeycom shroud sels on the T turine t unit No. 8 of TÉTs-. Figure 7 is plot of the vrition in the internl reltive efficiency of the high pressure cylinder ( o i ) s function of the fresh stem flow rte in this turine. Over the entire rnge of stem lod o i ws found to increse from.5% for fresh stem flow of 60 tons h to.68% for lods close to mximl (90 tons h), which corresponds to n increse in the power of the high pressure cylinder power y roughly.5 MW. According to the mnufcturers clcultions n increse of 0.7.0% in the efficiency ws expected. No other work esides instlling the honeycom shroud sels for stges ws done during the

5 A. S. Lisynskii et l. ç o i ç o i Reduced fresh stem flow, tons h Fig. 8. The vrition in the internl reltive efficiency of the high pressure cylinder of the K turine t unit No. 8 of the Perm GRÉS plnt of OGK- efore nd fter instlltion of honeycom shroud sels:,, first nd second stges of the tests; the flow rte is reduced to the nominl fresh stem temperture (50 C) Reduced fresh stem flow, tons h Fig. 9. The vrition in the internl reltive efficiency of the high pressure cylinder t cutoff of the stge 9 utomtic shutoff vlve of the K turine t unit No. of the Perm GRÉS plnt of OGK- efore nd fter instlltion of honeycom shroud sels:,, first nd second stges of the tests; the flow rte is reduced to the nominl fresh stem temperture (50 C). overhul tht could influence the chnge in the reltive internl efficiency of the high pressure cylinder. Another criterion for determining the effectiveness of updting the turine is to estimte the chnge in the stem lekge into the flow-through section of the high pressure cylinder sed on the discrepncy etween the dependences of the internl reltive efficiency of the high pressure cylinder in experiments with nd without regenertion instlled [7]. The discrepncy in the vlues of o i efore reconstruction ws out.%; fter reconstruction it did not exceed 0.%, which mens tht the totl lekge t the shrouds ws reduced. During moderniztion of the high pressure cylinder with reduction in the rdil gps in the shroud sels in order to mintin virtion resistnce of the shft line of the turine unit over the entire rnge of lods, it ws especilly importnt to tke specil cre in the repir opertions in the course of ssemling the turine unit while following the specifictions nd recommendtions of the mnufcturer, in prticulr: centering the elements of the flow-through section of the cylinder with sttements of the specified rdil nd xil gps, tking into ccount possile wrping of the collrs nd of the inner high pressure cylinder; centering of the rotors with respect to ores nd hlf-clutches; lignment of the slopes of the rotors with respect to the ering pins nd uniform distriution of the lod over the shft support tking into ccount their displcements during chnges in the therml stte of the turine; nd, repir of the ushings, nd checking nd fitting of the gps in the support erings of the turine. After reconstruction of four modernized T turines, low frequency virtion ws either entirely sent in the high pressure rotor erings (including in nominl opertion with N = 50 MW nd G = 900 tons h) or did not exceed level of 0. mm secec, in full greement with the specifictions [8]. Similr results were otined in tests fter instlltion of honeycom shroud sels in stges 0 of the high pressure cylinder of the K turine t unit No. of the Perm GRÉS plnt. Their design is close to tht shown in Fig. c (the tests were done y the Moscow rnch of the JSC SCPE ). Figure 8 shows tht the internl reltive efficiency of the cylinder incresed over the entire rnge of fresh stem flows. The lrgest increse of.8% (out.8 MW) ws recorded for nominl opertion of the turine unit (N = 800 MW, G = 500 tons h). The vritions in ç oi t the cutoff of the stge 9 utomtic shutoff vlve with modernized shroud sels for ll stges were still higher within the rnge of fresh stem flows (50 80 tons h) t.7 to.9% (Fig. 9). The lower solute mgnitude of the efficiency of this cutoff compred to the efficiency of the entire high pressure cylinder is explined y the influence of the regultor stge tht is unequipped with honeycom sels nd hs specific weight in the temperture drop for the stge 9 utomtic shutoff vlve tht is considerly higher thn for the cylinder s whole. The experimentl dt shown here confirm the clculted increse in o i y % otined y experts t the firm SKB Turin with hydrodynmic modelling of the lekge through honeycom shroud sels for ctul rdil gps set within the rnge ä = mm with centering of the flow-through section of the high pressure cylinder of this turine t the Perm GRÉS. Aout hlf the totl increse in the internl reltive efficiency of the high pressure cylinder y.8% my e ttriuted to the effect of modernizing the shroud sels, while the

6 Introduction of Honeycom Shroud Sels on MW Supercriticl Pressure Units 5 rest of the increse is the result of the repirs mde on the high pressure cylinder during the mjor overhul. CONCLUSIONS. The designs for honeycom shroud nd end sels reported here cn e instlled in the flow-through sections of MW supercriticl-pressure turine units.. Honeycom sels provide higher internl reltive efficiency of the high pressure cylinders thn the trditionl forms of sels employed in stem turines.. When the developer's recommendtions re followed, the instlltion of honeycom shroud sels in the high pressure cylinders of MW turine units does not led to low frequency virtions of the high pressure rotor. Experience lso shows tht in order to provide for prolonged relile opertion of honeycom sels, s of ny sels with smll gps, the design of stem turines must provide for concentricity of the cylinders nd rotors during prolonged opertion, different operting conditions, nd chnges in lod. Suitle opertionl mesures must lso e tken to ensure high purity of the stem fed into the turine nd tht there re no prticles formed y corrosion or oxidtion in the stem.. Given the positive experience with the introduction of honeycom designs, it is pproprite to test them in the regultor stge, s well s in the end nd intermedite sels of the high pressure cylinders of supercriticl stem turines nd to pln for their use in the development of the flowthrough sections of new high unit power turine units, including those with supercriticl stem (t = C, P 9 MP). REFERENCES. S. V. Ushinin, Experience with the introduction of honeycom sels in stem turines, Élektr. Stntsii, No.0, pp.8 (009).. V. F. Rezinskikh, G. D. Avrutskii, M. A. Fedorov, nd S. A. Bykov, Extending the service life of UTMZ T turines t JSC `Mosénergo', Élektr. Stntsii, No. 6 (006).. A. G. Kostyuk, V. G. Griin, B. N. Petrunin, A. S. Lisynskii, K. V. Gorlitsyn, nd S. V. Ushinin, Prcticl experience with the introduction of honeycom shroud sels in MW turine systems, in: Proc. Second All-Russin Sci.-Prct. Conf. Incresing the Opertionl Reliility nd Efficiency of Electric Power Plnts nd Power Systems, ÉNERGO-0, Izdtel'skii dom MÉI, Moscow (0).. A. G. Kostyuk, S. A. Serkov, B. N. Petrunin, nd A. A. Chistov, Experimentl justifiction of method for clculting the erodynmic exciting forces in turine mchinery sels, Teploénergetik, No. (99). 5. G. D. Brinerg, Yu. M. Brodov, A. A. Gol'derg, L. S. Ioffe, V. V. Kortenko, V. B. Novoselov, nd Yu. A. Skhnin, Stem Turines nd Turine Units of the Urls Turine Fctory, Aprio, Yekterinurg (00). 6. A. M. Skhrov, V. K. Konovlov, nd S. V. Ushinin, Results of the commercil introduction of honeycom shroud sels on 00 MW turine units, Élektr. Stntsii, No., 8 (00). 7. RD Method for Evluting the Engineering Stte of Stem Turine Units Before nd After Repirs nd Between Repirs [in Russin], Approved y the Deprtment of Science nd Technology of RAO EÉS Rossii, Decemer 0, Rules for Engineering Opertion of Electric Power Plnts nd Grids in the Russin Federtion [in Russin], Ministry of Energy of Russi, SPO ORGRÉS, Moscow (00).