HYBRID THERMOSYPHON/PULSATING HEAT PIPE: GROUND AND MICROGRAVITY EXPERIMENTS

Transcription

1 HYBRID THERMOSYPHON/PULSATING HEAT PIPE: GROUND AND MICROGRAVITY EXPERIMENTS D. Mangini a, M. Mameli c, D. Fioriti c, L. Araneo b, S. Filippeschi c, M. Marengo a,d a Dept. of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine (BG), Italy b Politecnico di Milano, Dipartimento di Energia, Via Lambruschini 4A, Milano, Italy c Università di Pisa, DESTEC, Largo Lazzarino 2, Pisa, Italy d School of Computing, Engineering and Mathematics, University of Brighton, BN2 4GJ, Brighton,UK. Brighton 4/5/2017 1

2 HIGHLIGHTS 2 INTRODUCTION: THE HYBRID THERMOSYPHON/PHP CONCEPT EXPERIMENTAL APPARATUS RESULTS ON GROUND AND IN MICROGRAVITY Brighton 4/5/2017 2

3 THE PULSATING HEAT PIPE NO NEED FOR EXTERNAL PUMPING WORK; SIMPLE CONSTRUCTION; LOW FABRICATING COSTS; LESS SIZE AND WEIGHT DUE TO THE LOWER MASS FLOW; Ԧg HIGH HEAT FLUXES. POSSIBILITY TO WORK WITHOUT GRAVITY Liquid slug Vapor bubble Brighton 4/5/2017 3

4 INNER DIAMETER TO HAVE A SLUG/PLUG FLOW? Inner diameter Qሶ But if the Inner Diameter will increase too much SLUG/PLUG FLOW How much is it possible to increase the Inner diameter in order to have a Slug/Plug Flow? THE CRITICAL DIAMETER DEPENDS BY SOME PARAMETERS STRATIFIED FLOW Brighton 4/5/2017 4

5 STATIC CRITERION THE CAPILLARY LIMIT CRITERION DYNAMIC CRITERION d cr, bo 2 g l v d Cr, Ga 160 l U l l l v g Capillary limit (Kew and Cornwell 1997) (Dynamic Criterion 0-g, Baldassari et al. 2013) GRAVITY FIELD Ԧg d cr, bo d Cr, Ga Brighton 4/5/2017 5

6 CRITICAL DIAMETER 4,2 mm INFLUENCE OF GRAVITY d Cr, Ga 160 l U l l l v g 3 mm STRATIFIED REGION 0,8 mm GRAVITY FIELD [M/S 2 ] FC-72 at 20 C D Ga [mm] U l =0.1 m/s Earth gravity level: g = 9.81 m/s 2 Microgravity: g = 0.01 m/s mm 4.2 mm Brighton 4/5/2017 6

7 EXPERIMENTAL APPARATUS ALL THE HEATERS ARE CONTROLLED INDIPENDENTLY TC14 TC12 TC10 TC11 TC13 TC15 PRESSURE TRANSDUCER 16 T-TYPE THERMOCOUPLES; ALUMINUM; A PRESSURE ID TRANSDUCER; = 3 MM; UNIFORM HEATING DISTRIBUTION OD FLUID = 5 FLOW MM; 5 VISUALIZATION U-TURNS EVAPORATOR ZONE; POSSIBILITY TO TEST DIFFERENT HEATING DISTRIBUTIONS AT THE EVAPORATOR TC0 NON-SYMMERICAL TC1 TC3 HEATING TC5 TC7 DISTRIBUTION TC9 FLUID: FC-72, (FR = 0.5); NON-UNIFORM HEATING DISTRIBUTION AIR COOLED 20 C; TC2 TC4 TC6 TC8 Brighton 4/5/2017 7

8 ON GROUND 3 mm g level = m/s 2 VAPOR BUBBLES THAT PASS THROUGH THE HIGHER PART g LIQUID AND VAPOR PHASE ARE STRATIFIED LIQUID PHASE Ramada Plaza Jeju Hotel, Jeju, Korea 4/5/2017 8

9 EFFECT OF THE HEATER POSITIONS ON GROUND MAIN OBJECTIVE: STABILIZATION OF THE TWO-PHASE FLOW IN A PREFERENTIAL DIRECTION The heating power is provided non symmetrically Brighton 4/5/2017 9

10 EFFECT ON NON-SYMMETRIC HEATING DISTRIBUTION 10 The asymetrical position of the heaters Alternation of up-headers and down-comers MAIN GOAL: Promotion of fluid flow circulation in a preferential direction Brighton 4/5/

11 TEST IN VERTICAL ORIENTATION 13.8 W/cm W/cm2 The non-simmetric heating distribution, improving the flow motion in a preferential direction, allows to dissipate higher global heat fluxes Brighton 4/5/

12 AND HORIZONTALLY ON GROUND? BEING A LOOP THERMOSYPHON ON GROUND, THE DEVICE DOES NOT WORK WHEN HORIZONTALLY PLACED! Brighton 4/5/

13 IN MICROGRAVITY 3 mm DOES THE DEVICE BECOME A PULSATING HEAT PIPE IN MICROGRAVITY? DOES THE DEVICE WORKS IN MICROGRAVITY CONDITIONS??? g level = m/s 2 The device was tested during the 61 and 63 ESA Parabolic Flight Campaign Brighton 4/5/

14 IN MICROGRAVITY? 17 Micro-g With a gravity field Hyper-g (1.8g) Injection Micro-g (±.05g) Brighton 4/5/

15 g: g: Slug/plug 1.8 g: g: Stratified flow activation flow flow 1g g 0 g g 4/5/2017 Brighton 4/5/

16 NON-UNIFORM HEATING DISTRIBUTION IN MICROGRAVITY Brighton 4/5/

17 THANK YOU FOR YOUR KIND ATTENTION!!! Daniele Mangini University of Bergamo Davide Fioriti University of Pisa, Italy Dott. Mauro Mameli University of Pisa, Italy Prof. Lucio Araneo Polytechnic of Milano, Italy Prof. Sauro Filipeschi University of Pisa, Italy Prof. Marco Marengo University of Brighton, UK Brighton 4/5/