1. Two-Phase Heat Transfer Laboratory Texas A&M University Experimental Study of Condensation on Micro Grooved Plates R. Barron-jimenez, H. Y. Hu, G. P. Peterson Department of Mechanical Engineering Texas A&M University

2. Two-Phase Heat Transfer Laboratory Texas A&M University Overview Introduction Experimental System –Apparatus –Test Plates –Test Conditions Results –Overall Condensation Heat Transfer Coefficient –Condensate Removal Conclusions

3. Two-Phase Heat Transfer Laboratory Texas A&M University Micro Grooves Scientific Interest Optimum geometry to take advantage of the surface tension Effect of vapor shear during condensation Role of gravitational body force during condensation Applications Condensate removal –Thin film Retain liquid –Enhance capillary pumping in micro heat pipes Better understanding of the condensation phenomena

4. Two-Phase Heat Transfer Laboratory Texas A&M University Experimental Apparatus

5. Two-Phase Heat Transfer Laboratory Texas A&M University Experimental Apparatus

6. Two-Phase Heat Transfer Laboratory Texas A&M University Experimental Apparatus

7. Two-Phase Heat Transfer Laboratory Texas A&M University Experimental Apparatus

8. Two-Phase Heat Transfer Laboratory Texas A&M University Test Plates Micro Grooves Geometry

9. Two-Phase Heat Transfer Laboratory Texas A&M University Test Plates

10. Two-Phase Heat Transfer Laboratory Texas A&M University Test Plates

11. Two-Phase Heat Transfer Laboratory Texas A&M University Test Conditions Vapor velocity :4.14±0.64 m/s Re (transition regime) :3.474*10 3 System pressure :101.35 kPa Plate orientation :Horizontal Cooling Temperature : 20, 35, 50, or 65ºC

12. Two-Phase Heat Transfer Laboratory Texas A&M University Test Conditions Constant Plate Temperature Assumption

13. Two-Phase Heat Transfer Laboratory Texas A&M University Results Overall Condensation Heat Transfer Coefficient Plate 5 vs. 3 (W) : 1.75 and 2.9 times larger  = 60º vs. 45º : 1.55 better

14. Two-Phase Heat Transfer Laboratory Texas A&M University Results Overall Condensation Heat Transfer Coefficient Average U h : 52%

15. Two-Phase Heat Transfer Laboratory Texas A&M University Results Condensate Removal Micro grooves in plate 5 are better than smooth surface

16. Two-Phase Heat Transfer Laboratory Texas A&M University Conclusions Data is not conclusive. Further work is recommended Large micro grooves with 60º apex angles tend to work better (best performance: Plate 5) Tests conditions improve the micro grooves performance Micro grooves help to maintain a stable condensation pattern Eliminate “wall channel” effect and reduce heat losses

17. Two-Phase Heat Transfer Laboratory Texas A&M University Questions? ¿ ¿ ? ?