The Piezoceramic Generator for SJ

Transcription

1 Th Pizorami Gnrator for SJ Dančová, Ptra 1, Vít, Tomáš 2 & Trávníčk, Zdněk 3 1 Ing., Dpartmnt of Powr Enginring Equipmnt, Thnial Univrsity of Libr, Hálkova 6, Libr 1, ptra.danova@tul.z 2 Ing., PhD., tomas.vit@tul.z 3 Ing., CS., Institut of Thrmomhanis, Aadmy of Sins of th Czh Rpubli, Doljškova 5, 182 Pragu 8, tr@it.as.z Annotation: Th rsults of th masurmnt and numrial analysis of pizorami gnrator for Synthti Jt (SJ) ar prsntd in this artil. Th masurmnt was basd on vibromtry prinipl; thr ar prsntd rsults of ignfrquny masurmnt, rsults of vloity masurmnt of mmbran ntr. Th rsults of numrial simulation using FEM ar also prsntd thr. Ky words: Synthti Jt (SJ), Pizorami transdur (PCT), Vibromtry, FEM simulation Introdution: Synthti Jts (SJ) ar jts of fluid, whih ar gnratd by priodi motion of fluid, whn th flow is xtrudd and sukd priodially into an orifi. Th main advantag of SJ is th zro-nt-mass-flux jt that liminats th rquirmnt of piping for th fluid inlt. Though th nozzl works with zro-nt-mass-flux, th momntum in z dirtion is non-zro. SJ has many signifiant appliations and th numbr of appliation is inrasing all th tim. Th most important appliations an b dividd into two main groups: 1) Th main (primary) flow ontrol: SJ is usd for jt vtoring, flow fild ontrol in xtrnal and intrnal arodynamis and for inrasing of intnsity of mixing. 2) Using of stand-alon SJ or systms of thm: SJ is usd for intnsifiation of th hat transfr. Pizorami Transdur: Th quipmnt for SJ an hav diffrnt dsign, but th main Fig.1 Th PCT

2 mhanism and prinipl is mostly th sam. In our masurmnt w hav usd th pizorami transdur (PCT) as an atuator. Th pizorami transdur (PCT) is usd as an atuator in many miroltronis or mdial appliations. W an mntion th us in miroltronis (miniatur ooling dvis) or in mdial appliation as nbulisrs or drug dosing dvis. Usag of th PCT as a puls gnrator has many signifiant advantags,.g. appliability in diffrnt fluids, in broad tmpratur rang, in havy duty failitis. Othr advantags of PCT ar long opration liftim and low powr onsumption. It is nssary to know stati and dynamis haratristi of PCT for a orrt dsription of th SJ funtion. PCT is omposd of two basi layrs th pizorami layr and th mtalli mmbran. Th pizorami matrial is usually basd on of th oxid of lad (Pb), zironium (Zr) and titanium (Ti) solid solutions and it is pizoltri ativ. Th mtalli mmbran is pizoltri nutral. Ths two layrs ar los fixd togthr. Th thin silvr layr is oatd on th on sid of pizorami to form an ltrod. Th sond ltrod is mostly formd from th mtal plat of pizoltri nutral layr. Physial dsription of th pizorami haratristis inluds lasti quation (1), ltri quation (2) and pizoltri quations of stat (3), (4) T = (1) D = (2) T = S E (3) ij ijkl kl ijk k Dk = kij Sij + ε kj E j (4) whr T, D, S, E,, and ε ar strss tnsor, vtor of ltri flux dnsity, strain tnsor, vtor of ltri fild, lasti moduli tnsor, pizoltri offiint tnsor and prmittivity tnsor. Stat quations dsrib intration btwn lasti and pizoltri proprtis of strutur. Thr ar som paramtrs in th form of lasti moduli tnsor, pizoltri offiints tnsor and prmittivity tnsor. Whn w tak in th aount th axi-symmtry of th pizoramis ths tnsors an b writtn in th matrix form as follows: = = ε11 ε = ε 11 ε 33 Vibromtry masurmnt: Th analysis of PCT is basd on Lasr Dopplr vibromtry prinipl. Lasr Dopplr vibromtry (LDV) is a non-ontat vibration masurmnt thniqu using th Dopplr Efft. Th LDV prmits masurmnt of hot, miniatur or soft surfas, vn undr watr, without mass-loading. A lasr Dopplr Vibromtr is basd on th prinipl of th dttion of th Dopplr shift of ohrnt lasr light that is sattrd from a small ara of th tst objt. Th objt sattrs or rflts light from th lasr bam and th Dopplr frquny shift is usd to masur th omponnt of vloity whih lis along th axis of th lasr bam.

3 Th Omtron VQ-1-D (B&K 8338) Portabl Digital vibromtr is usd for pris masurmnt of vloity of osillating mmbran. Thr ar th main paramtrs of vibromtr: Frquny rang:.5 22 khz Masurmnt rangs (full sal (pak)): 2 mm/s, 1 mm/s, 5 mm/s Spurious fr dynami rang (SFDR): > 9dB Bst rsolution:.2 µm/s/(hz)^,5 Th rspons of PCT on sinusoidal and squar driving signal at diffrnt frqunis was masurd. In both ass th frquny of driving signal was 5, 6, 1, 2 and 95 Hz. Th FFT analysis of rspons on singl puls was usd to dtrmin th ignfrqunis of pizorami transdur. Th LabViw softwar was usd to aquir and analyz th signal obtaind from Omtron vibromtr. Numrial simulations: A FEM simulation shows th possibility of numrial simulations of suh a omplx phnomnon as a pizoramis-atuator-fluid intration. Th papr shows th rsults of modal analysis and numrial simulation of dynami rspons on driving ltrial signal. For th orrt rsults of simulation it is nssary to st th boundary onditions and th matrial haratristi of PCT. Th usd matrials and boundary onditions ar shown at Fig. 7a. Th PCT was fixd on th primtr; th pizorami was fd with th voltag of ±1V on th top surfa, th voltag of th mtalli mmbran was kpt onstant on valu of V. Th matrial offiints of th ltromhanial haratristis ar lasti, pizoltri and diltri (s matrixs abov). Rsults: Th dtrmination of th PCT ignfrquny was th first stp of masurmnt. Th PCT ignfrquny was dtrmind from FFT of rspons on singl puls. It.5 is vidnt that th first.4 ignfrquny of th PCT.3 orrsponds to th valu of 96Hz (Fig.2)..2 Vibromtry masurmnt: Fig.3, 4 shows rsults of vibromtry masurmnt. In this as th driving signal was harmoni and had th frquny 5, 6, 1, 2 and 95Hz. Δz [mm] Fig.2 Rsults of FFT of rspons on singl puls Fig.3 Mmbran dviation in tim (sinusoidal driving signal) Voltag [V] f [Hz] 1-5Hz 2-6Hz 3-1Hz 4-2Hz 5-95Hz driv

4 Th valu of frquny 95Hz was los to th ignfrquny dtrmind in prvious xprimnts. Th amplitud of th atuating voltag on pizorami was adjustd to ±1V. Fig.3 shows th tim dviation of th ntr of mmbran. It is vidnt that th largst displamnt of mmbran ntr was ahivd at th frquny 95Hz whih was los to its ignfrquny (96Hz). Fig.4 shows th tim dviation of th vloity of th mmbran ntr. Th highst vloity was ahivd at th driving signal frquny 95Hz. Th valu of th vloity at 95Hz is at its maximum two ordrs highr than th vloity in othr xprimnts. That is why its rang is shown on th right sid axis. Fig.5 and 6 shows rsults of vibromtry masurmnt in as of squar driving signal at frqunis 5, 6, 1, 2 and 95Hz. Fig.5 shows th mmbran displamnts. Th pak valus of mmbran displamnt ar in all ass xpt th 95Hz lowr thn th rsults ahivd from th sinusoidal signal. Th pak valus and th shap of th tim dviation ar narly th sam for driving frquny 95Hz. It is also vidnt that th mmbran displamnt has for a driving frquny 95Hz harmoni haratr rgardlss of th squar haratr of th driving signal Fig.4 Th vloity of mmbran motion in tim (sinusoidal driving signal) Δz [mm] Fig.5 Mmbran dviation in tim (squar haratristi of driving signal) Voltag [V] Hz 2-6Hz 3-1Hz 4-2Hz 5-95Hz 1-5Hz 2-6Hz 3-1Hz 4-2Hz 5-95Hz driv 1-5Hz 2-6Hz 3-1Hz 4-2Hz 5-95Hz Fig.6 Th vloity of mmbran motion in tim (squar haratristi of driving signal)

5 Fig.6 shows th valus of mmbran vloitis whih ar muh highr than th vloitis that ar gnratd by harmoni signal. Consquntly th PCT fd with squar driving signal is mor powrful (has a highr pumping output) than PCT fd with harmoni signal. Whn th oprating frquny is los to th ignfrquny of PCT th rspons on th driving signal is narly th sam rgardlss of th shap of th driving signal. FEM simulation: Fig.7b shows th rsults from th modal analysis of th PCT. Th first ignfrquny orrsponds to 931.6Hz. It orrsponds to th valu 96Hz ahivd from vibromtry. Th small dviation in rsults is th aus of th inauray of usd valus of matrial proprtis in numrial simulation. ±1V V Fig 7a Usd matrials and boundary ondtions Fig.7b Th displamnt of mmbran by th first ignfrquny Conlusion: Th papr shows rsults of vibromtry masurmnt of movmnt of pizorami transdur and omparison with numrial simulation. Th influn of th shap (harmoni vs. squar) and th frquny of th atuating signal on rspons of th PCT ar pursud. Th influn of th frquny was prsupposd. Th largst dviations and th highst vloitis whr ahivd whn th frquny of th atuating signal was los to th ignfrquny of PCT. Th influn of th shap of atuating signal on rspons of th PCT is mor rmarkabl. Th usag of squar signal lads to th largst dviations, highst vloitis and highr powr of th PCT whn th frquny of th atuating signal is distant from th ignfrquny of PCT. Whn th frquny of th atuating signal is los to th ignfrquny of PCT th dviations and vloitis ar indpndnt on th shap of th atuating signal. Th omparison of rsults of xprimnts and numrial simulations shows th possibility of usag of a numrial simulation as a mthod for various physial phnomnon analyss. Th papr shows that th rsults of numrial simulations ar in grat agrmnt with rsults of xprimnts. Numrial modl should b usd for rliabl dsription of studid phnomnon.

6 Aknowldgmnt: W gratfully aknowldg th support by th Grant Agny of th Czh Rpubli GAČR 11/5/2681 and Rsarh Targt of th Ministry of Eduation of th Czh Rpubli - MSM Litratur: SMITH B. L., GLEZER A., Th formation and volution of synthti jt, Phys. Fluids, Vol 1, DANČOVÁ, P., 26. Studi proudění typu Synthti Jt, Diplomová prá, TU Libr, Czh Rpubli, (in Czh languag) DANČOVÁ, P.,VÍT, T., TRÁVNÍČEK, Z., 27. ANALYSIS OF SJ PIEZO-CERAMIC PULSATION GENERATOR, onfrn DEVELOPMENTS IN MACHINERY DESIGN AND CONTROL, in prparation TRÁVNÍČEK, Z., VOGEL, J., HOŠEK, J., VÍT, T. 25. Numrial simulation and flow vizualization of Synthti Jt, onfrn TOPICAL PROBLEMS OF FLUID MECHANICS 25, Institut of Thrmomhanis AS CR, Pragu, Fbruary 16-17, 25 OMETRON. Vibration masurmnt systms, From ERHART, J., 22. Pizolktriké hytré matriály pro lktrothniku., ELEKTRO 22/11, pp. 4-7 (in Czh languag)