Thing tin khoa hpc cong nghe m o
PHLTONG PHAP DO vA TINH TOAN CAC THONG SO KHI B O N G HOC TRONG MO HINH THLT NGHIEM
In the pievious paper In July's issue, the authors have intmduced about fhe selection ofthe experimental models for detemiining the aeiotlynamic peribnnances ofthe local ventilators.
In this paper, these authors refer to the methods for measuring and calculating the aerodynamic peiformances of the local ventilators on the selected experimental model
1 . M y d i u
Trong bai b i o s l 7/2016, n h i m t i e g i i da glfll thleg v l vise lya ehgn m l hinh t h f l nghl#m d l x i c djnh t h i n g s l d i n g hgc efla qggt gifl cue bg.Trong b i i b i o nay, nh6m t i e g i i t i l p tgc tgc l i m ro p h y y n g p h i p do v i tinh t o i n d c t h i n g s i khi dflng hge tren mfl hinh t h f l nghl0m d y y c lya ehgn.
Trong d n g t i e t h f l nghl#m quat g i i egc bg, d n phai cfl hg t h i n g t h i l t bj tao dong khi c h u y i n dflng do quat sinh ra va c i e t h i l t b| do d c t h i n g s l dflng^hpc cua dong khi, qua do tinh t o i n c i e thong s l n h i m x i y d y n g c i c d y y n g dgc tinh d a quat gio. O l t h y e hign d y y e ySu d u tren, eflng t i e do l y f l n g v i tinh toan d c thflng s i khi dgng hge dong vai t r i quan trgng.
2. B i t r i t h i l t bj d o c i c t h i n g s i d g n g hgc tren m i hinh thu> n g h i g m
T i t ca d c thflng s l d y y e g l i m s i t do luflng.
ThS. Le TRUNG TUYiN KS. PHAM X U A N THANH ThS. PHAM QUANG THAI Viin Khoa hoc Cdng nghi Md - Vinacomin
Biin tip: ThS. Pham Chin Chlnh tinh t o i n d u y c h i l n thi va ghi v i o m i y tinh theo thfli gian thyc.
ThiSt bi dd cic thdng so mdi tnrdng t?i diu vio ciia qu^t
T h i n g s l m i l t r y f l n g bSn n g o i i I n g khi dgng hge bao g i m ;
- Ap s u i t khi q u y l n d y y e do b i n g t h i l t bi do efl dai do (750 ~ 1250) hPa v i tin higu dflng dlgn phat ra (4 ~ 20)mA.
- Nhlgt dfl kho v i nhiSt dg y f l t d y y e do b i n g t h i l t b| do nhi#t dg cfl dai do (-50 ~ 250)0C, tin higu d i n g dlgn p h i t ra (4 ~ 20)mA.
- Dp I n do quat tao ra d y y e do b i n g t h i l t bj efl dai do (30 - 120) dB, tin higu dflng dign p h i t r a ( 4 ~ 2 0 ) m A .
Thiet bi do cic thdng s6 t$i diu ra cQa Quat PL2
Tai cfla ra cfla quat b i tri cac t h i l t bi do l y f l n g g i m c i :
c
1=>6 5Di + 0.23
" -0.00~
On9Ch\jy6n.j4, B^ninth^ng OngtoPtto
: i
B$ dl6u chlnh litu 'iKrng
D , B ^ „ linh^Jni- T.'^'"^ ' ^ « " " "^-^ IMng s6 ding hoc cia ddng khi quat gid cue bd
dd^S^itnhatV«^li'^I!l'"i-'^'''i''^''°'^'^^^
dd do tai mil phing sau mit phing do cOa ing Pito PL3. PL.,. PL; viPL, -MitphSng til cic vi tri 1. 2, 3;
Cua ra cua ing cfl bd phin diiu chlnh ihdng s6 Im luong cia ddng khL KHCNM sO 5/2016* AN TOAN MO
Thong tin khoa hoc cflng nghe mo - Thilt bi do i p suit tinh d d i l do (0 ~
10O(W)Pa. tin hl^u ding dlgn phat ra (4 - 20)mA, sy d i do theo hinh 2.
- Nhiet dg khfl dyye do bang thilt bi do nhl^t dg d dii do (-50 ~ 250)°C, tin higu dflng dlgn phitra(4~20)mA.
Thiet bi do cac thing so tgi mit phing PLg Khi quat quay, tao thinh dong khing khi bi xoiy theo d i l u quay d a quat. O l dim bao dong khong khi chgy thing I n dinh qua mat phang PL3 nyl efl b i tri d e cam biln do i p sgit dflng, phia tryflc mat phang PL3, phai dat bg nan thang dong khflng khi nhy hinh 3.
Tgi mat phing PL3, d c thilt bl do gim:
- Thilt bj do i p suit tinh efl dil do (0 - 10OOOjPa, tin hieu ding dlgn phit ra (4 ~ 20)mA sy d l do theo hinh 2.
- Nhlgt dg khi dyyc do bing thilt bl do nhlgt dfl CO dil do (-50 ~ 250)»C, tin higg dong diSn phitra(4~20)mA.
- Thilt bi do i p suit ding d 24 ing do Plto
w
eo dil do (0 - 2500)Pa, b i trf nhy hinh 4 v i Ing do Pito trong mat phang nhy hinh 6.
T/i/lf hi diiu chinh luv luvng ding khi Thilt bi d dang hinh chom d g elipsolt dyye dllg khiln bang ding ey - biln tin d l diig ehinh lyg lyyng theo j mgin.
3. Tinh toan c i c thong s i dgng hgc cua dong khi tiong dyfl'ng I n g thu- nghigm
Ty d c thflng s l do dyye theo thfli gian thyc vigc tinh toan d e thong s i dgng hge cfla ding khi nham xiy dyng cic dllm lim vl#e eua qgat tfl do, ve d i thi dyyng dae tinh qugt, cg t h l glni d cae thflng s i sag;
MitdQ khi quyen phia trudc diu vio quat mit phang PL1
Mat dg cfla khi quyln (PQ) phai duyc xie dinh tfl d c phep do eae thflng so HSn quan trong khu vye thfl nghigm v i dyyc tinh toin bing cich sfl dgng cflng thfle sau:
Hlnh2. Vdng do ip suit irnh cia ddng khi ddng Hlnh3. BdWi^Sthing ddng khi
Ban Mnh 0 5D
Hinh 4. M$t phing do cOa cSc Sng Pito
KHCNM SO 9/2016' AN TOAN Mfl
w
Thong tin khoa hoc cong nghe mo Pe = 3.25t^- + 1 8 . 6 t ^ + 692. Hg_ ( p b - 0 . 3 7 8 Pp) , „ , ^
° R(tao + 273,15) Trong do;
Po - Mdt dp khong khf moi tnrong, kg/m^.
Pe - Ap su^t hoi bao hoa. Pa.
pp - Ap suat ho-i thy« te. Pa.
Pb - Ap suat moi tru-o-ng, Pa.
R - Hing s6 chit khi R = 287,1 J/kgK.
tjjQ - Nhipt d6 kho do du-pc or m6i frirang, °C.
t^Q- Nhi^t dp yot do du-pc a moi tnpcmg. °C.
M$t dp khdng khi trong 6ng din Mdt dO cua ddng khf trong ong din t^i mgt phing X (py^) du'pc tinh bang cong thiJc sau;
kg/m^
p ( t , „ + 273.15 w g ^ _ ^ y ' "^"W,, -^ 273,15 A Pt / Trong do:
Px - Mit dg khing khi tgi mat phang x, kg/ml Pg- M#t dfl khong khi mil injiong, kg/m'.
tdx - Nhlgt dfl do dyye tgi mit phing x, °C.
Psx - Ap suit ttnh do dyye tgi mgt phang x.
Pa.
Mit dd khdng khi qu9t
Mat dg khflng khi quat (p) phil duyc tinh tfl mat dg eua khflng khi trong khi quyln (p_), ap suit tinh o diu vio qugt (Pj^) va nhlgt dfl fl diu vio qugt {t^{j sfl dgng eong thfle-
kg/m»
„ _ „ /•^i+5>Wtdo+ 273,15 \ Trong dfl:
Psi - Ap suit tmhVmgt phang PL^, Pa.
tsi - Nhlgt dfl tgi mit phang 1, "C.
, Oil vfli Ing thfl nghl#m nhy hinh 1 efl dig vao ty do diu ra d Ing khi dfl:
- Ap suit tTnh tai diu ing thy l i ap suit mil tnrflng vl vjy Pj^ = o Pg.
- NhlSt dfl do tai mat phang PL, l i nhlgt dg
mil tnrong tflu = tsi.
Kit qua mat dfl khong khi tai mit phing PL1 d i n h l i mat dg mil tnrong p.= p^.
Ngoai ra, mjt dg khing khi tgi bit d vi tri nio (ni phg thuflc vio i p suit ttnh v i nhlgt dg do tgi vi trf dfl) eung dyyc tinh theo cflng \i\irc sau:
P = (Pb + PsdoW Cdo * T)kg/m'.
Trong dfl:
p - Mat dg khflng khi tgi v| trf do trong ing thy kg/m=.
Pb - Ap suit mil trydng do dyyc bing baromet. Pa.
Psdo " Ap s"^t tmh do dyyc bang v i i do. Pa.
R - Hing s i ehit khi R = 287,1J/kgK.
T - Nhlgt dfl tuySt dii (273,15 + tjo) K.
•do- Nhlgt dfl do dyyc tgi dllm do thy nghiim, °C.
Tai t(jo = O'C, Pb = 101315 Pg, thl mit do khflng khi p^ = 1,293 kg/m'.
Bdnhdt
BS nhflt cfla khflng khi dyye tinh theo dng thfle:
tl = (17,23 +0,48 tc|)E-06 Cic gia trf cfla khflng khi a 20°C l i 1,819E- 06 Pa.s, d t h l dyyc sfl dgng fl' dil nhllt d i tfl (4 - 40)»C.
Ap suit Odng cua ddng khi tm mit phing PL3 Ap sgit dgng cfla dflng khi tai mat phing PL3 (Pv3) dyye tinh theo cflng thfle sau:
Trong dfl:
i^l-
Pv3 - Ap suit dflng trung binh do dyyc byi 24 ing Plto eit ngang duflng ing tai m|t phing PI-3. Pa-
Pv3r" Ap suit dflng do dyyc cfla tflng ing Plto trong mit phing d t ngang PL 3, Pa.
n-Si cic ing Plto dyye sfl dyng dk do n=24.
Vin tdc tmng binh cia ddng khi VJn t i c trung binh tgi mit phing PL3 (V3) dyye tinh tfl eing thfle sau:
KHCNM SO 9/2016- A N T O A N MO
Thong tin khoa hoc conq nghe m o
Trong do:
V3 - La vgn tic dflng khi tai mgt phang s i 3 nyi dgt eac ing do Plto, m/s.
P3 - Mat dfl khflng khi tgi mat phing dgt inq Pito. I^ni=.
Luu lupng tgi mit phing Oo
Luu luyng d a quat thir nghigm (Q) tgi mgt phing sfl 3. nyi dat d e ong Pito eit ngang se duyc tinh tfl eong thfle:
Q3 = V3A3, mVs Trong do:
(33 - Luu lyyng cua quat tai mat phing so 3 nWs.
A3-Dign tieh mat cat ngang tai mat phing dgt ong Pito, m^.
Luu lupng cua quat d dieu kiin thir nghiim Luu lyyng quat or dilu kign thfl nghigm (Q) duyc tinh toan tiieo d n g thfle:
Cflng thuc tfnh nhy sau:
Trong do:
- f: Hg s i ma sit dyyc x i c dinh theo d n g thyc:
f — ''•^*
' ~ l> 0.17
"«
- R^: Chi s i Reynolds dya vao dirong kinh ong thy nghigm (D3) dyyc tinh tCr d n g thuc:
R . = D„aVp
^ = ^3©.
Trong dfl:
Q - Luu lyyng thyc t l d a quat y dilu kign mfli tnrong, mVs.
p - Mgt dp khong khi mfli tryong, kg/m'.
^ suit Odng cua qugt ddSeukiin thir n^Hm Khi d e phSp do bing Ing pito d t ngang duyc tlHTC hiln.ipsultdflngtaiciraradaquat mSt phing PL2 (Pv2) duyc xie d|nh tfl vige si>
dgng eac i p suit ding (P^):
•©•©•'
Trong do:
Pv2 - Ap suit dgng tai cua ra d a quat Pg.
A2 - Di^n tich mat cat ngang tai cua ra cua quat (vfli mfl hinh nhy hinh 1 thi A2 = A3), m'.
Khi sy khie nhau giua P , v i P . , it hyn 1 kPa,dthleoip2=p3,
Khi do: Pv2 = Pv3
Ap suit long d a qugt d mil phing PL2 Ap suit ting cua quat phai dyye tinh t d n tfl cie phep do i p suit dgng P^g, i p suit tinh P , , tai mit phang PL3 v i t i n thit i p suit t i l h dyyng ing ty mit phing PL2 d i n mgt phjng PL3-
D(,3 - Buflng kinh Ing gifl thy nghl#m, m.
V - V#n tie dflng khi, m/s.
p - Mat dg khong khi, kglm'.
M - Og nhH khflng khi, Pg 5
^- Le: Chilu d i l tyyng dyyng d a b i nan thang, m.
- Ty lg d a d i l u dil tirong dyyng d a doan thing (Le) vfli duflng kinh ing thy (Dh3) duyc xic dinh ttr dg day d e phin Hr (y) v i dyyng kinh tyyng dyong (D):
L, 15.04
' ' " ° [ . - 2 6 . 6 5 © . 1 8 4 . . g / f
Cong thuc niy la i p dgng cho ing tron thing.
Ap suit tong ^u vio
B i i vyi diu vao ty do, khi d e quat hflt tnjc Bip ti> khflng khi, R1 se dyye xem xet bang vfli i p suat khi quyln, do dfl:
A • , Pt1=''.Pa Ap suat tdng cua qugt
Ap suit ting d a quat (P() a dilu kien thy nghigm dyyc tinh nhy sau:
P, = P | 2 - P , i , Pg
Bay l i mgt bilu thfle dgi s l nlu P., l i am P.
se la s i Ion hon Pt2.
Cong suit diu vio qugt d diiu kign thir nghigm
KHC.V M sO 9/2016- AN TOAN MO
Thdng tin khoa hoc cong nghe mo
Khi dpng ca dipn du-p'c SLP dung, c6ng suat dau v^o quat (H) co th§ dupc do luwng tO cong suat (^0n dau vao cua dpng ca (W) va hipu suat SCP dung cOa dpng ca (q):
H = Wn,W Cong suit ra cua quat
Cong su^t ra cua qugt (HQ) se ti !§ vai luu lupng (Q) va ap su^t tong (P^) do quat tao ra, neu khdng khi khong chju nen.
Vi khong khi chju nen, hipu Ong nhiet dpng anh huang dau ra va hp s6 nen (Kp) phat dupc ap dgng trong khi tfnh cong su^t ra cua qugt:
Ho = QPtKp_W Trong do;
HQ - CSng su^t tren d^u ra cua qugt thu nghidm, W.
Q - Luu lupng do qugt tgo ra, m^/s.
Pt - Ap suat t6ng do qugt tgo ra, Pg.
Kp - Hp s6 nen.
- H§ so nen (Kp) c6 t h l dupc xac (^nh tu cac cdng thuc sau;
Pti + Pb
nn(l -t- x)\ / z \ '[ X I llnCl + z ) / Cdc thdng s6 P^, P^., pj,, H va Q la t^t ca cac gid tri thu nghipm. So mu entropy (y) co t h l dupc Ily la 1.4 cho khdng khf.
HiSu suat tong cua qu^t
Hi§u suit t6ng cua qugt (qt) la ty lp giOa cdng suit diu ra vS diu vao quat dupc xac djnh theo cdng thuc;
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Hinh 6 C^c duitng dSc tfnh cQa qu^t du-Q/c xic dfnh sau khi thO-nghi$m
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Higu suit tinh ciia quat
Higu suit t?nh d a quat (qs) cd t h l dyyc tinh tfl hieu suit ting d a qugt (qt) v i ty le eua i p suit tTnh v i i p suit ting efla quat:
3. KSt lugn
o l xic dinh duyc eio duflng dje tinh efla qugt gifl cgc bg, vi#c do dgc v i tinh toin cie thing s i dgng hgc d a dflng khi do quat tgo ra rit quan trgng, inh hyyng quylt djnh din kit qua thu- nghidm.
Cic thflng s l do dae va tinh toin dyyc gifli thigu trong bii la ein thilt d l xiy dyng duyc dyyng djc tinh, tuy nhien d l xiy dyng duyc dying dgc tinh cfla qugt egc bg cfln cin efl nhflng quy trinh, nhflng phyyng phip thfl nghiem khoa hgc, ding tin d y , sS duyc nhflm tie gia glfll thiiu trong d c s i tilp theo.
Til" llgu tham khao:
1. Air Movement and Control Association In- ternational, Inc and American Society of Heating, Refrigerating and Alr-Condltlonlng Engineering, Ine (2000), Laboratory Methods of Testing fans tor Aerodynamic Perfomianee Rating ANS1/AMCA210-99.
2. Japanese Standards Association (2000), JIS B 8330:2000 Testing methods forturbo-fans.
KHCNM sO 9/2016* AN TOAN MO
