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nuha nuha

on 9 January 2013

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Transcript of SPF

Results and Discussion 1 6 IntroductionExchanger to Heat 2 3 Design of a Compact Heat Exchanger Procedure The final dimensions of the heat exchanger Fuente: Red Española Pacto Mundial - Enero 2012 2. Transparencia PROGRESAR IdP Mesas cuadradas
Casos de Implantación
Grupos de Trabajo
Talleres de implantación Transparencia Foros de diálogo y aprendizaje Promover la RSE a través de los 10 Principios PACTO MUNDIAL SPF 4 7 Summary Introduction to Heat Exchangers
Design of a Compact Heat Exchanger
Superplastic Forming
Finite Element Model
Results and Discussions
Summary Table of contents 4% representación sector seguros 8% representación sector Servicios Financieros, banca y seguros 8,42 de nota media satisfacción en los eventos 2011 85% de satisfacción en atención al Socio (Encuesta 2011) 65 Socios Empresa Grande no Cotizada 11% del total de Informes de Progreso presentados 21% del total de Formatos Libres presentados Fraternidad Muprespa
DKV Seguros
Mutua Universal Nuestros Socios: 15% Publicación de Buenas Prácticas Reporting y Benchmarketing Tu sector en el Pacto Mundial Valoración de nuestros socios Contamos con... U n i v e r s i t y o f J o r d a n
Faculty of Engineering & Technology
Mechanical Engineering Department
Final Year Project
2012-2013 Design And Superplastic Forming of a Compact Heat Exchanger Done by :
Nuha Aljuneidi 0084410
Rania Asha 0097931

Supervised by :
Dr . Firas S.Jarrar Thickness distribution
Pressure profile
Forming time
Stress and strain distribution
Effect of number of channels
Effect of friction
Effect of aspect ratio
Effect of strain rate A heat exchanger is a specialized device that assists in the transfer of heat from one fluid to the other. Applications -Air conditioners
-Space heaters
-Chemical processing Compact heat exchangers High surface area to volume ratio:
- Greater than 700m²/m³ (gas-gas applications)
-Greater than 400m²/m³ ( liquid-gas applications) Heat Exchanger Types -Double pipe heat exchangers
-Shell and tube heat exchangers Heat Exchanger Types -Plate heat exchangers
-Plate-Fin Heat exchangers Heat Exchanger Design considerations -Pressure drop
-Operating temperature
-Log mean temperature difference
-Fouling of Heat Exchangers A plate fin heat exchanger has to cool a hot-air gas stream, with a cold-air stream. - Steady -state conditions.
-Heat losses are negligible.
-Wall thermal resistance is distributed uniformly.
-No phase changes.
-Longitudinal heat conduction is negligible.
-The individual and overall heat transfer coefficients are constants. Assumptions Superplastic Forming -A tool for fabrication of very complex shapes.
-Integrated structures lighter and stronger than the assemblies they replace. Superplastic Forming Applications Superplastic Forming Process Advantages of SPF Process -Form complex components.
-One step process.
-Elimination of unnecessary joints and rivets.
-Reduction of subsequent machining.
-Minimizes the amount of scrap produced. -Low production rate .

-Uneven thickness distribution .

-Cost of superplastic sheets. Disadvantages of SPF Process 5 Finite Element Model ABAQUS software has been used to
simulate three die geometries; triangular, trapezoidal and rectangular -Isothermal condition.
-Plane strain condition.
-Microstructure evolution was not taken into consideration.
-The superplastic material has isotropy properties.
Assumptions Die Geometry Triangular channel Trapezoidal Channel Rectangular Channel Material Constitutive Model Power law equation: Flow stress Constant Strain Strain rate sensitivity Strain hardening exponent Strain rate Mesh Convergence Study Thank You ! Thickness Distribution Trapezoidal fins COF= 0.25 ,target strain rate = 0.001 s^-1 Thinning factor = tmin/tavg Thickness Distribution Pressure profile Trapezoidal Rectangular Pressure profile Stress and Stain Distribution Effect of the number of Channels Effect of Friction on Pressure profile Effects of Aspect RatioThickness distribution Effects of Aspect Ratio on Thickness distribution Friction Coefficient With Aspect Ratio SPF of the geometries that have aspect ratios of 0.57 & 0.9 are not recommended for COF=0.15 The geometry that has an aspect ratio of 0.9 became potentially acceptable for SPF for COF=0.35 -Severe thinning problem can be improved by increasing the COF
-However, for higher COF = 0.5, the geometry that has an aspect ratio of 0.57 is still not recommended for SPF. -At high strain rates, failure in the AA5083 alloy is as a result of the necking
-On the other hand increasing the strain rate cause to decrease the forming time. Effect of Strain Rate •The design procedure combines pressure drop analysis with the manufacturing requirements using FEM. An ideal design is one that has a combination of desired properties such as ; -High heating load.
-Uniform thickness distribution.
-Low forming time. It was found that the forming time and pressure profile are the same for all sheets with different number of channels • Non uniform thickness distribution can be effectively enhanced using variable friction distribution along the die. An optimum value of strain rate must be chosen to guarantee a good forming quality. •Consider alternative technique to very deep channel. Thickness Distribution Trapezoidal fins COF=0.25 and target strain rate of 0.001 s^-1 Rectangular Fins With COF=0.15 , target strain rate of 0.001 s^-1. Triangular fins COF=0.35 ,target strain rate = 0.001 s^-1 Best thickness distribution Pressure
Profile Changes in sheet thickness Forming
strain rate Sheet’s radius of curvature Die-sheet
interaction Coefficient
of friction. Triangular Rectangular Triangular
Trapezoidal Triangular channel, 1.576 hr (5673 sec) Trapezoidal Channel ,0.7 hr(2520 sec) Rectangular Channel:, 1.842 hr,( 6630sec).
The longest forming time Forming time -Geometry .
-Friction coefficient.
-Strain rate. Effect of Friction on Thickness distribution Effects of Friction on Forming time The friction condition at the die-sheet interface strongly affects the metal flow during the forming process. Effect of Friction The value of COF at which transition occurs represents the optimal friction distribution, where the maximum thinning factor can be obtained. Effect of Aspect Ratio on Pressure profile Effect of Aspect Ratio -Aspect ratio = W/D.
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