ENEN TCP.B6L7.B1: ANALYTICAL AND NUMERICAL EVALUATION OF UNEXPECTED HEATING LHC Collimation Working Group M. Garlasché A. Bertarelli, F. Carra, M. Calderon, A. Dallocchio, L. Gentini

ENEN EN-MME-PE Marco Garlasché TCP Geometry 204/09/2012 Ref. dwg LHCTCP__0002 2x T-sensor Pt100(Al 2 O 3 case) Glidcop CuNi 304L stainless steel AC 150 Carbon-Carbon

ENEN Temperature Data 04/09/2012EN-MME-PE Marco Garlasché ISSUES: General unexpected heating up Cooling down times in the order of days Inconsistency between T sensors (left vs. right; left upstream vs. downstream) 3 17 th July 27 th July Interesting intervals Pt100 readout sets: T [C] time T [C] time

ENEN EN-MME-PE Marco Garlasché4 Summary Unexpected heating:  Analytical evaluation of possible cooling conditions (active cooling vs. radiation)  FEM validation (static & transient)  Analytical estimation of instant power deposition Inconsistency of left jaw temperature data  Eccentric P deposition?  Positioning of sensors? Conclusions 04/09/2012

ENEN EN-MME-PE Marco Garlasché5 Unexpected heating – active cooling? Fit with only convection (unphysical) leads to heat transfer coeff. values around 4.5 W/m2K (in the range of free convection..) 04/09/2012 Active cooling is not present! Analytical fit of T data (17 th July) Only active cooling (i.e. convection from water flow in pipes) the model used..

ENEN 04/09/2012EN-MME-PE Marco Garlasché6 Unexpected heating – what about only radiation? Q RAD T AMB ε SS =0.3 ε CC =0.7÷0.9 ε Cu =0.05÷0.15 Analytical fit of T data (17 th July) Only radiation 1 jaw considered Consistent material data ‘Only radiation’ condition is compatible with T data! TANK1 JAW the model used..

ENEN 04/09/2012EN-MME-PE Marco Garlasché7 CaseActive Cooling Contact between absorber & other components (*) P [W] needed for constant 65°C 1√√4300 2X√13 3√X14 4XX7 Unexpected heating – what about only radiation? Results consistent with an. estimation WE CAN RULE OUT: Case 1 – out of range P and t intervals.. (*) Except cooling pipes in case 3 Symmetric FEM analysis Power on absorbers such that initial temperature is met in correspondence of the T sensor

ENEN 04/09/2012EN-MME-PE Marco Garlasché WE CAN RULE OUT: Case 3 - not an equilibrium condition Unexpected heating – what about only radiation? Case 3 with reduced active cooling (1 W/m2K)

ENEN 04/09/2012EN-MME-PE Marco Garlasché9 Unexpected heating– instant power deposition Only case 2 & 4 analysed Upgraded analytical model considers presence of other jaw P deposition per jaw at different jaw gaps determined starting from T data (17th-24th July) Model benchmarked with estimations (B. Salvant) from RF induced power loss. Case 4 WE CAN RULE OUT: Case 4 – less likely, low P values TANK Case 2

ENEN INCONSISTENCY OF LEFT JAW TEMPERATURE DATA 04/09/2012EN-MME-PE Marco Garlasché

ENEN 04/09/2012EN-MME-PE Marco Garlasché Left jaw Temperature data Can inconsistency be given by eccentric P deposition? P LEFT =0 W P RIGHT =9 W I.o.t obtain similar T, deposition should be completely eccentric… Case 2 Is inconsistency given by detached T sensor? No contact Case 2 Contact Absence of contact causes only tenths of degree difference T [C] time

ENEN 04/09/2012EN-MME-PE Marco Garlasché Left jaw Temperature data Left Jaw max temperatures and cool down profile are not compatible with nominal cooling condition absence of active cooling T [C] time Cool-down curve of left jaw should ‘quickly’ meet the one of right jaw..

ENEN 04/09/2012EN-MME-PE Marco Garlasché CONCLUSIONS Unexpected heating:  High T & long cool down intervals, nominal option (1) not possible  Absence of equilibrium and low estimated P, option 3 & 4 not likely  Most likely option is nominal contact between components and no active cooling (i.e. heat evacuation only through radiation)  Good agreement between analytical and FEM evaluations Inconsistency of left jaw temperature data  No active cooling also on left jaw  T LEFT vs. T RIGHT : eccentrical P deposition highly unlikely  T upstream vs. T downstream :sensor not in contact with jaw may only partly cause difference  Sensor not working properly? Readout calibration?

ENEN 04/09/2012EN-MME-PE Marco Garlasché Further slides

ENEN 04/09/2012EN-MME-PE Marco Garlasché Material Properties: ρ [Kg/m3]C [J/kgK]K [W/mK] AISI 304L Glidcop AC150 C-C &31 CuNi Al2O3--30

ENEN 04/09/2012EN-MME-PE Marco Garlasché16 Unexpected heating – what about only Radiation? Case 1: active cooling ( √ ) contact ( √ ) Case 2: active cooling (X) contact (√) Case 3: active cooling ( √ ) contact (X)Case 4: active cooling (X) contact (X)

ENEN 04/09/2012EN-MME-PE Marco Garlasché Emiss Cu 0.15 Emiss Cu 0.05 Q RAD T AMB ε SS =0.4 ε CC =0.7÷0.9 ε Cu =0.05÷0.15 An. Estimation: Comparison for different in range emissivity of Glidcop & CuNi

ENEN 04/09/2012EN-MME-PE Marco Garlasché Left jaw Temperature data Is inconsistency given by detached T sensor? Case 2 eccentric P deposition No contact Case 2 Contact Absence of contact causes only tenths of degree difference

ENEN 04/09/2012EN-MME-PE Marco Garlasché Temperature Data Comparison with nominal working cooling system (same position on B2) PT100 on beam 1 PT100 on beam 2 70 °C 27 °C

ENEN DATA SET : 27 th July 04/09/2012EN-MME-PE Marco Garlasché20

ENEN DATA SET : 17 th July 03/08/2012EN-MME-PE