Строительная теплофизика / 5

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<eZ^bfbjkdbc =hkm^Zjkl\_gguc mgb\_jkbl_l

DZn_^jZ l_ieh]ZahkgZ[`_gby \_glbeypbb b ]b^jZ\ebdb

Dmjk e_dpbc ih ^bkpbiebg_³ &ljhbl_evgZy l_iehnbabdZ´>ey klm^_glh\ ki_pbZevghklb hqgh]h h[mq_gby

KhklZ\bl_ev < F Dhg^jZrh\

<eZ^bfbj

L_iehmklhcqb\hklv h]jZ`^_gby

G_klZpbhgZjguc l_ieh\hc j_`bf

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L_iehmklhcqb\hklv HD m^h[gh ijhke_^blv bamqZy bo l_fi_jZlmjguc j_`bf ijb i_jbh^bq_kdbo l_ieh\uo \ha^_ckl\byo >_ckl\bl_evgu_ i_jbh^bq_kdb_ dhe_[Zgby W b 4 ihlhdh\ hdheh ih\_joghklb HD qZklh fh`gh [_a hkh[hc ih]j_rghklb aZf_gblv ijZ\bevgufb ]Zjfhgbq_kdbfb dhe_[Zgbyfb beb kmffhc (∑ ) jy^Z ]Zjfhgbd Ihwlhfm

aZdhghf_jghklb i_jbh^bq_kdh]h l_ieh\h]h 4 \ha^_ckl\by gZ HD bf_xl ijyfh_ ijZdlbq_kdh_ ijbeh`_gb_ K\hckl\h l_iehmklhcqb\hklb HD bgl_j_km_l gZk \ ^\mo gZijZ\e_gbyo

l_iehmklhcqb\hklv HD hlghkbl_evgh dhe_[Zgbc W b 4 ihlhdh\ \ ihf_s_gbb jbk Z

l_iehmklhcqb\hklv HD hlghkbl_evgh kd\hagh]h ijhgbdZgby dhe_[Zgbc Wg q_j_a _]h lhesbgm HD \ ihf_s_gb_ jbk [

Jbk L_iehmklhcqb\hklv HD b __ ^\hcgh_ ijhy\e_gb_±hlghkbl_ dhe_[Zgb_ W\ b 4 ihlhdZ \ ihf_s_gbb Z b hlghkbl_evgh_ kd\hagh_ ijhgbdZgb_ q_j_a HD \ ihf_s_gb_ dhe_[Zgbc Wg gZjm`gh]h \ha^moZ [

L_iehmklhcqb\hklv HD jZkkfZljb\Z_lky ih f_lh^bd_ ijb\_^_gghc \ KGbI,, ©Kljhbl_evgZy l_iehl_ogbdZª

L_iehmklhcqb\hklv HD d dhe_[Zgbyf l_ieh\uo ihlhdh\ \ ihf_s_gbb

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< = $T $τ

?keb kehc j_adbo dhe_[Zgbc W aZdZgqb\Z_lky \ ij_^_eZo i_j\h]h hl ih\_joghklb\gmlj_gg_c fZl_jbZevgh]h kehy b ke_^h\Zl_evgh _]h l_ieh\Zy bg_jpby ' > lh < jZ\_g m^_evghfm dhwnnbpb_glm l_iehmk\h_gby fZl_jbZeZ wlh]h kehy 6

]^_ 5 6 λ Fρ khhl\_lkl\_ggh l_jfbq_kdh_ khijhlb\e_gb_ dhwnnbpb_gl l_iehmk\h_gby l_iehijh\h^ghklv b fZkkh\Zy l_ieh_fdhklv fZl_jbZeZ i_j\h]h kehy

< dhwnnbpb_gl l_iehmk\h_gby \lhjh]h fZl_jbZevgh]h kehy

Dhe_[Zgby W ih\_joghklb hlklZxl \h \j_f_gb hl dhe_[Zgbc l_ieh\h]h ihlhdZ ijhoh^ys_]h q_j_a ih\_joghklv gZ \_ebqbgm ε \ jbk

Wlh hlklZ\Zgb_ k^\b] ih nZa_ ^ey ijhkl_cr_]h kemqZy

ε \ = 7

]^_ 7 i_jbh^ \j_f_gb q

Jbk Hlghkbl_evgu_ \h \j_f_gb dhe_[Zgby W \gmlj_gg_c ih\_joghklb HD

l_fi_jZlmju \ha^moZ \ ihf_s_gbb b l_ieh\h]h ihlhdZ ijhoh^ys_]h q_j_a wlm ih\_joghklv

Baf_g_gb_ l_ieh\h]h ihlhdZ lZd`_ k\yaZgh k dhe_[Zgbyfb W \ha^moZ \ ihf_s_gbb Khhlghr_gb_ f_`^m baf_g_gbyfb T ijhoh^ys_]h q_j_a ih\_joghklv HD b W \ha^moZ hfu\Zxs_]h wlm ih\_joghklv hij_^_eyxlky dhwnnbpb_glhf l_iehih]ehs_gby < ih\_joghklb HD

MjZ\g_gb_ fh`gh i_j_ibkZlv \ \b^_

Ba dhlhjh]h ke_^m_l qlh khijhlb\e_gb_ l_iehih]ehs_gbx < ∑ khijhlb\e_gbc l_iehmk\h_gbx < b khijhlb\e_gbx l_iehh[f_gm α % gZ ih\_joghklb

Baf_g_gb_ W \ha^moZ hi_j_`Z_l \h \j_f_gb W ih\_joghklb gh hlklZ_l hl baf_g_gby l_ieh\h]h ihlhdZ gZ \_ebqbgm ε % jbk

ε % = 7

L_iehmklhcqb\hklv HD kd\haghfm ijhgbdZgbx dhe_[Zgbc W gZjm`gh]h \ha^moZ

Dhe_[Zgby W gZjm`gh]h \ha^moZ \uau\Zxl dhe_[Zgby ih\ur_gby ihgb`_gby W b l_ieh\uo ihlhdh\ T \ lhes_ b gZ \gmlj_gg_c ih\_joghklb gZjm`guo HD Ih f_j_ m^Ze_gby hl gZjm`ghc ih\_joghklb dhe_[Zgby W \ lhes_ h]jZ`^_gby mf_gvrZxlky ih

\_ebqbg_ b aZiZa^u\Zxl \h \j_f_gb ih nZa_ Dhe_[Zgby τ \gmlj_ggbo ih\_joghkl_c g_ihkj_^kl\_ggh \ebyxl gZ l_iehihl_jb b jZ^bZpbhggmx W5 ihf_s_gbc ihwlhfm __ baf_g_gby ij_^klZ\eyxl hkh[uc bgl_j_k ijb ijh_dlbjh\Zgbb hlhie_gby ihf_s_gbc K\hckl\h l_iehmklhcqb\hklb kd\haghfm ijhgbdZgbx l_fi_jZlmjguo dhe_[Zgbc oZjZdl_jbam_lky ^\mfy ihdZaZl_eyfb

AZlmoZgby ν b aZiZa^u\Zgby ε

IhdZaZl_ev kd\hagh]h aZlmoZgby dhe_[Zgby W ν hij_^_ey_l \h kdhevdh jZa Zfieblm^Z baf_g_gby W gZ \gmlj_gg_c ih\_joghklb HD $τ % f_gvr_ Zfieblm^u dhe_[Zgbc Wg $W+

NhjfmeZ ^ey jZkq_lZ ν bf__l \b^

]^_ 5L b 6L khijhlb\e_gb_ l_iehijh\h^ghklb b dhwnnbpb_gl l_iehmk\h_gby fZl_jbZevguo keh_\ HD

khijhlb\e_gby l_iehijh\h^ghklb lhesbgu HD ∑ 5L

ihke_^h\Zl_evghklb jZkiheh`_gby hkgh\guo dhgkljmdlb\guo b l_iehbaheypbhgguo

keh_\ _keb bo fh`gh q_ldh \u^_eblv \ HD dhlhjZy mqblu\Z_lky ihijZ\hqguf dhwnnbpb_glhf β ke

'

]^_ bg^_dku ijb 6 hij_^_eyxl iheh`_gb_ hkgh\guo keh_\ ih oh^m l_fi_jZlmjghc \hegul _ ba ihf_s_gby gZjm`m

gZebqby \ HD \ha^mrghc ijhkehcdb dhlhjh_ mqblu\Z_lky ihijZ\hqguf dhwnnbpb_glhf β \i

]^_ 5\i khijhlb\e_gb_ l_iehi_j_^Zq_ \ha^mrghc ijhkehcdb

Ijb[eb`_gghc nhjfmehc fh`gh ihevah\Zlvky lhevdh \ lhf kemqZ_ _keb fh`gh q_ldh \u^_eblv \ dhgkljmdpbb h]jZ`^_gby ^\Z hij_^_eyxsbo \ l_ieh\hf hlghr_gbb kehy

< hklZevguo kemqZyo g_h[oh^bfh ihevah\Zlvky [he__ keh`gufb nhjfmeZfb ijb\_^_ggufb \ KGbI,,

IhdZaZl_ev aZiZa^u\Zgby \h \j_f_gb kd\hagh]h ijhgbdZgby l_fi_jZlmjguo dhe_[Zgbc ε \ hkgh\ghf aZ\bkbl lhevdh hl ' b jZ\_g

ε ≈ ( ' − )7

ijb 7 qZkZ ε = '

Nhjfmehc ke_^m_l ihevah\Zlvky lhevdh ijb '! khhl\_lkl\mxsbo i_jbh^m

L qZkZ

Ijb ' \_ebqbgZ ν ijZdlbq_kdb jZ\gZ k\h_fm PLQ \hafh`ghfm agZq_gbx

ν = ν PLQ = 5 5%

]^_ 5 khijhlb\e_gb_ l_iehi_j_^Zq_ HD

5% khijhlb\e_gb_ l_iehh[f_gm gZ \gmlj_gg_c ih\_joghklb HD

< ijhba\hevguc fhf_gl \j_f_gb = gZqZeh hlkq_lZ khhl\_lkl\m_l PD[ W gZjm`gh]h \ha^moZ W \gmlj_gg_c ih\_joghklb HD τ % fh`_l [ulv hij_^_e_gZ mjZ\g_gb_f

?keb gZ HD h^gh\j_f_ggh ^_ckl\mxl baf_g_gby Wg b W\ \ ihf_s_gbb lh fh`gh \hkihevah\Zlvky ijbgpbihf kmi_jihabpbb keh`_gby g_aZ\bkbfuo l_ieh\uo \ha^_ckl\bc b ihemqblv j_amevlbjmxs__ baf_g_gb_ W\ keh`_gb_f __ qZklguo baf_g_gbc ih^ \ebygb_f dZ`^h]h \ha^_ckl\by

L_iehmklhcqb\hklv ihf_s_gby

L_iehmklhcqb\hklvx ihf_s_gby gZau\Z_lky k\hckl\h ih^^_j`b\Zlv hlghkbl_evgh_ FRQVW WQ ijb i_jbh^bq_kdb baf_gyxsboky l_iehihklmie_gbyo

Bgl_gkb\ghklv dhe_[Zgbc WQ \ ihf_s_gbb [m^_l lZd`_ aZ\bk_lv hl kl_i_gb g_jZ\ghf_jghklb emqbklhc b dhg\_dlb\ghc khklZ\eyxsbo l_iehhl^Zqb HI b bo khhlghr_gby

Ih oZjZdl_jm baf_g_gby \h \j_f_gb \k_ \hafh`gu_ \b^u l_iehihklmie_gbc b l_iehihl_jv fh`gh jZa^_eblv gZ ]Zjfhgbq_kdb_ b ij_ju\bklu_ ;he__ keh`gu_ kemqZb l_iehi_j_^Zqb fh]ml [ulv ij_^klZ\e_gu bo khq_lZgb_f

Bf__lky hij_^_e_ggZy ki_pbnbdZ mqZklby emqbkluo b dhg\_dlb\guo l_iehihklmie_gbc \ l_iehmklhcqb\u_ ihf_s_gby dhlhjZy khklhbl \ jZaghc ihke_^h\Zl_evghklb i_j_^Zqb 4 \ha^mom b ih\_joghklb ihf_s_gby

Ijb jZkkfhlj_gbb aZ^Zqb l_iehmklhcqb\hklb ihf_s_gbc ihevamxlky f_lh^hf gZeh`_gby kmi_jihabpbb hkgh\Zgguf gZ g_aZ\bkbfhklb ^_ckl\by hl^_evguo l_ieh\uo \hafms_gbc Kh\f_klguc wnn_dl ^_ckl\by \k_o bklhqgbdh\ b klhdh\ l_iehlu ihemqZxl kmffbjh\Zgb_f ∑ qZklguo j_amevlZlh\

Dhwnnbpb_gl g_jZ\ghf_jghklb l_iehhl^Zqb HI ijb i_jbh^bq_kdhf hlhie_gbb fh`gh hij_^_eblv ih nhjfme_

F = (4PD[ − 4PLQ ) 4FS

]^_ 4FS 4PD[ 4PLQ kj_^gyy PD[ b PLQ l_iehhl^ZqZ HI

?keb l_iehhl^ZqZ ijb[hjZ baf_gy_lky ih aZdhgm ijZ\bevgh]h ]_jf_lbq_kdh]h dhe_[Zgby lh

(4PD[ − 4PLQ ) = :4

]^_ $4 Zfieblm^Z baf_g_gby l_iehhl^Zqb

>ey l_ieh_fdbo ijb[hjh\ dhwnnbpb_gl F fh`_l [ulv hij_^_e_g wdki_jbf_glZevgh

L_iehmklhcqb\hklv ihf_s_gby hij_^_eyxsmx baf_g_gby _]h l_ieh\h]h j_`bfZ fh`gh hoZjZdl_jbah\Zlv ihdZaZl_e_f l_iehmk\h_gby <QRf b l_iehih]ehs_gby Jihf

< dZq_kl\_ ihdZaZl_ey l_iehmk\h_gby ihf_s_gby <QRf ijbf_gyxl ∑ _ l_iehmk\h_gb_ \k_o ih\_joghkl_c HD h[jZs_gguo \ ihf_s_gb_

<QRf = ∑ <L $L

]^_ <L $L dhwnnbpb_glu mk\h_gby b iehsZ^b hl^_evguo h]jZ`^_gbc \ ihf_s_gbb

IhdZaZl_ev l_iehih]ehs_gby Jihf \ hkgh\ghf mqblu\Z_l ih]ehsZl_evgmx kihkh[ghklv HD Jh]j B \ha^mohh[f_g J\_g b jZ\_g bo kmff_

Jihf = Jh]j + J\_g

Ijb ij_ju\bklhc ih^Zq_ l_iehlu dhwnnbpb_gl l_iehih]ehs_gby HD jZ\_g

]^_ Ω dhwnnbpb_gl ij_ju\bklhklb hij_^_ey_lky \ aZ\bkbfhklb hl hlghr_gby \j_f_gb hlhie_gby d h[s_fm i_jbh^m L qZkZ

L_iehih]ehs_gb_ \ ihf_s_gbb \ j_amevlZl_ \_glbeypbhggh]h \ha^mohh[f_gZ jZ\gh

J\_g = / Fρ

Ih^jh[g__ kf ;h]hkeh\kdbc b ^j Hlhie_gb_