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Resultados experimentais Prática 2 - Aletas Dimensões das Aletas Diâmetro (mm) Comprimento (cm) Alumínio 9.8 56.3 Alumínio: k= 237 W/m2 Aço inox 1 9.6 56.3 Aço Inox: k = 15,1W/m2 Aço inox 2 10.42 56.3 Orifício 1 2 3 4 5 6 7 8 9 Extremidade Distância (cm) 0 3.5 8.4 13.3 20.7 28.2 35.5 42.9 50.4 56.3 Regime Transiente Regime Permanente Temperatura na Caldeira (°C) 60 Orifício:1 Orifício Distância Temperatura (°C) Tempo (min) Temperatura da Aleta (°C) Alumínio Aço Inox 1 Aço Inox 2 Alumínio Aço Inox 1 Aço Inox 2 1 0.00 43.90 39.30 41.60 0 25.20 25.10 25.00 2 3.50 40.80 34.00 35.60 5 25.90 25.70 25.40 3 8.40 37.20 29.30 30.80 10 26.90 26.80 26.00 4 13.30 34.90 27.70 28.40 15 28.10 27.90 27.00 5 20.70 32.30 26.70 26.70 20 29.10 28.70 27.90 6 28.20 30.30 26.20 26.10 25 30.50 30.20 29.30 7 35.50 29.00 26.00 26.00 30 32.30 32.00 30.60 8 42.90 28.30 25.90 25.90 35 33.90 34.40 33.50 9 50.40 28.30 25.90 25.90 40 37.80 37.40 36.30 Extremidade 56.30 27.60 25.90 25.90 45 38.70 38.20 36.10 50 41.00 40.60 39.10 55 42.30 41.70 40.60 60 43.60 42.70 40.60 65 43.20 39.80 40.90 70 43.00 42.20 41.10 75 43.90 39.30 41.60 Cálculo de h Dados: Tamb(°C)= 25.9 Alumínio Alumínio - Caso 1: Convecção na extremidade Alumínio - Caso 2: Aleta com extremidade adiabática Alumínio - Caso 3: Aleta com extremidade adiabática Alumínio - Caso 4: Aleta infinita θb (K)= 18.00 h = 16.3443576888 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 16.3846250603 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 16.0162883587 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 14.9986274323 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 D (m) = 0.01 m = 5.2521818153 0 18.00 18.00 0.00 0 0 m = 5.2586476997 0 18.00 18 0.00 0 0 m = 5.1992028533 0 18.00 18.00 0.00 0 0 m = 5.0313158444 0 18.00 18 0.00 0 0 L (m) = 0.563 0.03 14.90 15.39 -0.49 0.2410075783 0.4909252268 0.03 14.90 15.3882475523 -0.49 0.2383856723 0.4882475523 θL (K)= 1.7 0.03 14.90 15.41 -0.51 0.2629800083 0.5128157645 0.03 14.90 15.4781953601 -0.58 0.3343098745 0.5781953601 AF (m2) = 0.0177657065 0.081 11.30 11.80 -0.50 0.2542730412 0.5042549367 0.081 11.30 11.7989425932 -0.50 0.2489437113 0.4989425932 0.081 11.30 11.85 -0.55 0.2999875062 0.5477111521 0.081 11.30 11.9751680248 -0.68 0.4558518617 0.6751680248 k (W/(m K)) = 237 0.131 9.00 9.12 -0.12 0.013544313 0.1163800371 0.131 9.00 9.1101654036 -0.11 0.0121364162 0.1101654036 0.131 9.00 9.17 -0.17 0.0279663385 0.1672313921 0.131 9.00 9.3116786604 -0.31 0.0971435874 0.3116786604 P (m) = 0.0314159265 0.204 6.40 6.29 0.11 0.0127726944 0.1130163459 0.204 6.40 6.2813908819 0.12 0.0140681229 0.1186091181 0.204 6.40 6.33 0.07 0.0045266605 0.0672804612 0.204 6.40 6.4493756369 -0.05 0.0024379535 0.0493756369 Ac (m2)= 0.0000785398 0.28 4.40 4.33 0.07 0.0047793555 0.0691328832 0.28 4.40 4.33 0.07 0.0052552216 0.0724929075 0.28 4.40 4.36 0.04 0.0017448052 0.0417708658 0.28 4.40 4.3999946344 0.00 0 0.0000053656 AF( Adiabatica) (m2) = 0.0176871666 0.354 3.10 3.10 -0.00 0.0000000013 0.0000357889 0.354 3.10 3.10 -0.00 0 0.0000049784 0.354 3.10 3.10 -0.00 0 0.0000002266 0.354 3.10 3.03 0.07 0.0045978596 0.0678075189 0.43 2.40 2.33 0.07 0.0051375337 0.0716765909 0.43 2.40 2.33 0.07 0.0044968781 0.0670587664 0.43 2.40 2.29 0.11 0.0120799767 0.1099089473 0.43 2.40 2.07 0.33 0.109779492 0.331329884 0.505 2.40 1.94 0.46 0.2156284792 0.4643581367 0.505 2.40 1.95 0.45 0.2056651982 0.4535032505 0.505 2.40 1.85 0.55 0.3065629721 0.5536812911 0.505 2.40 1.42 0.98 0.9634612023 0.9815605953 0.545 1.70 1.85 -0.15 0.0232735392 0.1525566753 0.545 1.70 1.87 -0.17 0.0281154223 0.1676765406 0.545 1.70 1.73 -0.03 0.0008066164 0.0284009934 0.545 1.70 1.16 0.54 0.2917445607 0.5401338359 FO= 1.9823366216 FO= 1.9767011105 FO= 2.0288010942 FO= 3.535254882 Aço Inox 1 Aço Inox 1 - Caso 1: Convecção na extremidade Aço Inox 1 - Caso 2: Aleta com extremidade adiabática Aço Inox 1 - Caso 3: Aleta com extremidade adiabática Aço Inox 1 - Caso 4: Aleta infinita θb (K)= 13.40 h = 10.6288123323 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 10.6288099047 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 10.6288104893 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 10.6288102477 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 D (m) = 0.01 m = 16.7796883934 0 13.40 13.40 0.00 0 0 m = 16.7796864771 0 13.40 13.4 0.00 0 0 m = 16.7796869385 0 13.40 13.40 0.00 0 0 m = 16.7796867478 0 13.40 13.4 0.00 0 0 L (m) = 0.563 0.03 8.10 8.10 -0.00 0 0.0000000278 0.03 8.10 8.1000005005 -0.00 0 0.0000005005 θL (K)= 0.00 0.03 8.10 8.10 -0.00 0 0.0000002131 0.03 8.10 8.100000347 -0.00 0 0.000000347 AF (m2) = 0.0177657065 0.081 3.40 3.44 -0.04 0.0017777114 0.042162915 0.081 3.40 3.4421634738 -0.04 0.0017777585 0.0421634738 0.081 3.40 3.44 -0.04 0.0017776965 0.042162738 0.081 3.40 3.4421630947 -0.04 0.0017777266 0.0421630947 k (W/(m K)) = 15.1 0.131 1.80 1.49 0.31 0.0976384675 0.3124715467 0.131 1.80 1.49 0.31 0.0976381968 0.3124711135 0.131 1.80 1.49 0.31 0.0976391813 0.3124726889 0.131 1.80 1.49 0.31 0.0976386939 0.312471909 P (m) = 0.0314159265 0.204 0.80 0.44 0.36 0.1317608342 0.3629887521 0.204 0.80 0.44 0.36 0.1317605607 0.3629883754 0.204 0.80 0.44 0.36 0.1317643032 0.3629935305 0.204 0.80 0.44 0.36 0.1317624345 0.3629909565 Ac (m2)= 0.0000785398 0.28 0.30 0.12 0.18 0.031651631 0.1779090525 0.28 0.30 0.12 0.18 0.0316513452 0.1779082493 0.28 0.30 0.12 0.18 0.0316578711 0.1779265891 0.28 0.30 0.12 0.18 0.0316546085 0.1779174205 AF( Adiabatica) (m2) = 0.0176871666 0.354 0.10 0.04 0.06 0.0041863464 0.0647019818 0.354 0.10 0.04 0.06 0.0041860129 0.0646994039 0.354 0.10 0.04 0.06 0.0041942258 0.0647628429 0.354 0.10 0.04 0.06 0.0041901184 0.0647311239 0.43 0.00 0.01 -0.01 0.0000991434 0.0099570768 0.43 0.00 0.01 -0.01 0.0000993257 0.0099662269 0.43 0.00 0.01 -0.01 0.0000948512 0.0097391568 0.43 0.00 0.01 -0.01 0.0000970755 0.0098526917 0.505 0.00 0.00 -0.00 0.0000100266 0.0031664805 0.505 0.00 0.00 -0.00 0.0000102314 0.0031986634 0.505 0.00 0.00 -0.00 0.000005757 0.0023993702 0.505 0.00 0.00 -0.00 0.0000078345 0.0027990167 0.545 0.00 0.00 -0.00 0.0000046206 0.002149549 0.545 0.00 0.00 -0.00 0.0000048952 0.002212513 0.545 0.00 0.00 -0.00 0.0000004207 0.0006486494 0.545 0.00 0.00 -0.00 0.0000020466 0.0014305811 FO= 0.9755073822 FO= 0.9756085196 FO= 0.9731057789 FO= 0.9743571412 Aço Inox 2 Aço Inox 2 - Caso 1: Convecção na extremidade Aço Inox 2 - Caso 2: Aleta com extremidade adiabática Aço Inox 2 - Caso 3: Aleta com extremidade adiabática Aço Inox 2 - Caso 4: Aleta infinita θb (K)= 15.70 h = 11.0779468373 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 11.0779483812 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 11.0779152631 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 h = 11.0779324468 X(m) θexp θcalc θexp-θcalc (θexp-θcalc)2 (θexp-θcalc)1/2 D (m) = 0.0142 m = 14.375633369 0 15.7 15.7 0 0 0 m = 14.3756343708 0 15.7 15.7 0 0 0 m = 14.3756128824 0 15.7 15.7 0 0 0 m = 14.3756240318 0 15.70 15.7 0.00 0 0 L (m) = 0.563 0.03 9.7 10.2000418852 -0.5000418852 0.250041887 0.5000418852 0.03 9.7 10.2000417053 -0.5000417053 0.250041707 0.5000417053 θL (K)= 0 0.03 9.7 10.2000456735 -0.5000456735 0.2500456756 0.5000456735 0.03 9.70 10.2000435654 -0.50 0.2500435673 0.5000435654 AF (m2) = 0.0252741443 0.081 4.9 4.899999928 0.000000072 0 0.000000072 0.081 4.9 4.899999942 0.000000058 0 0.000000058 0.081 4.9 4.8999999941 0.0000000059 0 0.0000000059 0.081 4.90 4.90 0.00 0 0.0000001928 k (W/(m K)) = 15.1 0.131 2.5 2.3880002488 0.1119997512 0.0125439443 0.1119997512 0.131 2.5 2.3880008495 0.1119991505 0.0125438097 0.1119991505 0.131 2.5 2.387988747 0.112011253 0.0125465208 0.112011253 0.131 2.50 2.39 0.11 0.0125451936 0.1120053285 P (m) = 0.0446106157 0.204 0.8 0.8361570165 -0.0361570165 0.0013073298 0.0361570165 0.204 0.8 0.8361595104 -0.0361595104 0.0013075102 0.0361595104 0.204 0.8 0.8361082954 -0.0361082954 0.001303809 0.0361082954 0.204 0.80 0.84 -0.04 0.001305654 0.036133834 Ac (m2)= 0.0001583677 0.28 0.2 0.2804800893 -0.0804800893 0.0064770448 0.0804800893 0.28 0.2 0.2804879764 -0.0804879764 0.0064783143 0.0804879764 0.28 0.2 0.2803256052 -0.0803256052 0.0064522029 0.0803256052 0.28 0.20 0.28 -0.08 0.006465247 0.0804067598 AF( Adiabatica) (m2) = 0.0251157766 0.354 0.1 0.0969947828 0.0030052172 0.0000090313 0.0030052172 0.354 0.1 0.0970178347 0.0029821653 0.0000088933 0.0029821653 0.354 0.1 0.0965431032 0.0034568968 0.0000119501 0.0034568968 0.354 0.10 0.10 0.00 0.0000103655 0.0032195429 0.43 0 0.0330963353 -0.0330963353 0.0010953674 0.0330963353 0.43 0 0.0331651637 -0.0331651637 0.0010999281 0.0331651637 0.43 0 0.0317476374 -0.0317476374 0.0010079125 0.0317476374 0.43 0.00 0.03 -0.03 0.0010534179 0.0324564002 0.505 0 0.0129235184 -0.0129235184 0.0001670173 0.0129235184 0.505 0 0.0131258623 -0.0131258623 0.0001722883 0.0131258623 0.505 0 0.0089585485 -0.0089585485 0.0000802556 0.0089585485 0.505 0.00 0.01 -0.01 0.0001219306 0.0110422172 0.545 0 0.0095568189 -0.0095568189 0.0000913328 0.0095568189 0.545 0 0.0099164262 -0.0099164262 0.0000983355 0.0099164262 0.545 0 0.0025102382 -0.0025102382 0.0000063013 0.0025102382 0.545 0.00 0.01 -0.01 0.0000386058 0.0062133543 FO= 0.787260704 FO= 0.7878780181 FO= 0.775164154 FO= 0.7815211951 Encontrar h por solver: Xm = distância dos orificios teta exp = diferença entre T e T amb Estimar h e calcular m pela equação com m e h, calcular teta cal, pelas equações para cada caso calcular as diferenças e raiz da raiz, obteve-se a FO e pelo solver foi minimizada obteve-se h Comparando os tipos de aletas Caso 1: Covecção na extremidade Caso 2: Aleta com extremidade adiabática Caso 3: Aleta com temperatura conhecida Caso 4: Aleta infinita Alumínio Aço Inox 1 Aço Inox 2 x (cm) T exp T calc x (cm) T exp T calc x (cm) T exp T calc Caso 1 Caso 2 Caso 3 Caso 4 Caso 1 Caso 2 Caso 3 Caso 4 Caso 1 Caso 2 Caso 3 Caso 4 0.000 43.90 43.90 43.90 43.90 43.90 0.000 39.30 39.30 39.30 39.30 39.30 0.000 41.60 41.60 41.60 41.60 41.60 3.500 40.80 41.29 41.29 41.31 41.38 3.500 34.00 34.00 34.00 34.00 34.00 3.500 35.60 36.10 36.10 36.10 36.10 8.400 37.20 37.70 37.70 37.75 37.88 8.400 29.30 29.34 29.34 29.34 29.34 8.400 30.80 30.80 30.80 30.80 30.80 13.300 34.90 35.02 35.01 35.07 35.21 13.300 27.70 27.39 27.39 27.39 27.39 13.300 28.40 28.29 28.29 28.29 28.29 20.700 32.30 32.19 32.18 32.23 32.35 20.700 26.70 26.34 26.34 26.34 26.34 20.700 26.70 26.74 26.74 26.74 26.74 28.200 30.30 30.23 30.23 30.26 30.30 28.200 26.20 26.02 26.02 26.02 26.02 28.200 26.10 26.18 26.18 26.18 26.18 35.500 29.00 29.00 29.00 29.00 28.93 35.500 26.00 25.94 25.94 25.94 25.94 35.500 26.00 26.00 26.00 26.00 26.00 42.900 28.30 28.23 28.23 28.19 27.97 42.900 25.90 25.91 25.91 25.91 25.91 42.900 25.90 25.93 25.93 25.93 25.93 50.400 28.30 27.84 27.85 27.75 27.32 50.400 25.90 25.90 25.90 25.90 25.90 50.400 25.90 25.91 25.91 25.91 25.91 56.300 27.60 27.75 27.77 27.63 27.06 56.300 25.90 25.90 25.90 25.90 25.90 56.300 25.90 25.91 25.91 25.90 25.91 Cálculo das taxas e eficiências Dados: Tamb(°C)= 25.9 Alumínio Caso 1: Covecção na extremidade Caso 2: Aleta com extremidade adiabática Caso 3: Aleta com temperatura conhecida Caso 4: Aleta infinita θb (K)= 18.00 D (m) = 0.01 h = 16.3443576888 Qf = 1.7505109345 h = 16.3846250603 Qf = 1.7524892077 h= 16.0162883587 Qf = 1.734345809 h= 14.9986274323 Qf = 1.685746683 L (m) = 0.563 m = 5.2521818153 ηf = 0.3364079087 m = 5.2586476997 ηf = 0.3359603863 m = 5.1992028533 ηf = 0.3401285152 m = 5.0313158444 ηf = 0.3530287084 AF (m2) = 0.0177657065 θL = 1.7 k (W/(m K)) = 237 P (m) = 0.0314159265 Ac (m2)= 0.0000785398 AF( Adiabatica) (m2) = 0.0176871666 Aço inox 1 Caso 1: Covecção na extremidade Caso 2: Aleta com extremidade adiabática Caso 3: Aleta com temperatura conhecida Caso 4: Aleta infinita θb (K)= 13.40 D (m) = 0.01 h = 10.6288123323 Qf = 0.2666585502 h = 10.6288099047 Qf = 0.2666585195 h= 10.6288104893 Qf = 0.2666585335 h= 10.6288102477 Qf = 0.2666585271 L (m) = 0.563 m = 16.7796883934 ηf = 0.105854106 m = 16.7796864771 ηf = 0.105854118 m = 16.7796869385 ηf = 0.1058541177 m = 16.7796867478 ηf = 0.1058541176 AF (m2) = 0.0177657065 θL = 0.00 k (W/(m K)) = 15.1 P (m) = 0.0314159265 Ac (m2)= 0.0000785398 AF( Adiabatica) (m2) = 0.0176871666 Aço inox 2 Caso 1: Covecção na extremidade Caso 2: Aleta com extremidade adiabática Caso 3: Aleta com temperatura conhecida Caso 4: Aleta infinita θb (K)= 15.70 D (m) = 0.0142 h = 11.0779468373 Qf = 0.539721955 h= 11.0779483812 Qf = 0.5397219828 h= 11.0779152631 Qf = 0.5397213775 h= 11.0779324468 Qf = 0.5397216954 L (m) = 0.563 m = 14.375633369 ηf = 0.1235562002 m = 14.3756343708 ηf = 0.1235561894 m = 14.3756128824 ηf = 0.1235564202 m = 14.3756240318 ηf = 0.1235563013 AF (m2) = 0.0252741443 θL = 0.00 k (W/(m K)) = 15.1 P (m) = 0.0446106157 Ac (m2)= 0.0001583677 AF( Adiabatica) (m2) = 0.0251157766 eficiencia: Qf / Qmax Qmax = h . A. teta exp Eficiência (ηf) Taxa de transferência de calor da aleta (Qf (W)) Caso 1 Caso 2 Caso 3 Caso 4 Caso 1 Caso 2 Caso 3 Caso 4 Alumínio 0.336408 0.3359603863 0.340129 0.353029 Alumínio 1.7505 1.7525 1.7343 1.6857 Aço inox 1 0.105854 0.105854 0.105854 0.105854 Aço inox 1 0.2667 0.2667 0.2667 0.2667 Aço inox 2 0.123556 0.123556 0.123556 0.123556 Aço inox 2 0.5397 0.5397 0.5397 0.5397
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