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Published byAdrian Owens Modified over 8 years ago
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Experiences and Issues with Carbon Foam at BNL & Yale BNL: David Lynn, Marc-Andre Pleier, Anatoli Gordeev, Russ Burns, Ken Sexton Yale: Paul Tipton, Will Emmet, Tom Hurteau
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Three sources of CF foams considered Koppers Poco Allcomp Koppers is closed-cell and has an extremely non-uniform cell size Poco varies in density through thickness Allcomp is open-cell, has a fairly uniform pore size-easiest to machine and can manufactured in different densities All are more-or-less comparable in cost Note higher density
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Allcomp has been used for the Stave/Stavelet 09 Program BNL/Yale uses CGL thermal gel at the foam/tube interface Concerns about migration of CGL through Allcomp open-cell foam Solution: apply coating of Hysol to foam surface and cure prior to CGL and tube assembly Before and after Applied to inner endpiece Applied to outer endpiece
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Poco top/Koppers k-foam bottom Allcomp 0.5 g/cc Allcomp with hysol seal Open vs closed CGL drawn away Seal? Difficult, needs more work Need to compare machining again and cell sizes Note jagged edge
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Possible solution to Allcomp “ragged edge” problem (per DL) Create a 1-2 mm thick layer of Hysol on interface surface of foam and allow to cure; Machine with ball endmill as before; Apply coating of Hysol as before to seal pores on semi-cylindrical surface… Apply Hysol layerMachine foam as before Note improved edge
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Problem of tube-foam interface stresses Do we want a rigid bond (Hysol), a flexible bond (CGL thermal gel), or no bond at all (conduction across 25-50 micron air gap)? Anatoli Gordeev, BNL mechanical engineer has done a detailed ANSYS FEA of a quarter model of the tube-foam interface. A worst-case scenario of zero bond gap was assumed. A more detailed analysis of the no-bond option is pending.
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Gordeev, BNL 8-18-077 POCO FOAM – SS 304 PIPE CONNECTION STUDY 0.1mm box mesh POCO FOAM K=125, UNIFORM; E = 0.5 GPa; CTE = 0.7x10 - 6 SS 304 K =16.2 CTE = 1x10 - 5 BONDED CONTACT
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Gordeev, BNL 8-18-078 POCO FOAM – SS 304 PIPE CONNECTION STUDY TEMPERATURE LOAD INNER PIPE SURFACE 1.PIPE : L =80mm; OD = 2.77mm; ID = 2.17mm. 2.FOAM: 50mm long; 12.7mm wide; 4mm height. 3.¼ TAKEN FOR ANALYSES
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Gordeev, BNL 8-18-079 POCO FOAM – SS 304 PIPE CONNECTION STUDY T – DISTRIBUTION. VIEW # 3
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Gordeev, BNL 8-18-0710 POCO FOAM – SS 304 PIPE CONNECTION STUDY THERMAL LOAD ONLY; SYMMETRICAL CONSTRAINT
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Gordeev, BNL 8-18-0711 POCO FOAM – SS 304 PIPE CONNECTION STUDY TOTAL DEFORMATION; VIEW # 1
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Gordeev, BNL 8-18-0712 POCO FOAM – SS 304 PIPE CONNECTION STUDY TOTAL DEFORMATION; VIEW # 3
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Gordeev, BNL 8-18-0713 POCO FOAM – SS 304 PIPE CONNECTION STUDY EQUIVALENT STRESS; VIEW # 1
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Gordeev, BNL 8-18-0714 POCO FOAM – SS 304 PIPE CONNECTION STUDY EQUIVALENT STRESS; VIEW # 4
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Gordeev, BNL 8-18-0715 POCO FOAM – SS 304 PIPE CONNECTION STUDY SHEAR STRESS; VIEW # 1
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Allcomp Foam Thermal Conductivity Measurements (per Dave Lynn) Foam AL Calibration Block Foam SS Calib Block Al Measurement gives K = 79 W/m-K SS Measurement gives K = 93 W/m-K
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