Since high precision of working fluid charging is key to the evaluation of thermal performance, a novel perfusion method of a micro heat pipe (MHP) is presented. The MHP has a length of 26 mm, width of 20 mm and a thickness of ∼2.2 mm. The predetermined quantity of perfusion is 25 or 35 μl. Small volume and large capillary force render conventional vacuum perfusion methods quite impractical. To realise microscale and high precision of perfusion, the method of combining vacuum perfusion using a peristaltic pump and weight comparison before and after working fluid charging was used. The charging deviation of the method was <2 μl. After perfusion and sealing, the thermal performance testing of a MHP, which is engineered in light-emitting diode (LED) heat dissipation, was conducted and the input power varied from 1 to 7 W. The results show that high-power LEDs can reach the status of heat balance and can work steadily, and the maximum deviations of actual and simulated temperatures are 4.5 and 5.1°C, respectively, and the relative errors are 6.1 and 7.3%. Therefore, this perfusion method can be used for the working fluid perfusion of the MHP and makes it feasible for use in packaging manufacture of heat pipes.

References

1. 1)
  - 1. Lin, Z., Wang, S., Huo, J., et al: ‘Heat transfer characteristics and LED heat sink application of aluminum plate oscillating heat pipes’, Appl. Therm. Eng., 2011, 31, (14–15), pp. 2221–2229 (doi: 10.1016/j.applthermaleng.2011.03.003).
2. 2)
  - 20. Wang, X.D., Zou, L.L., Liu, J.G., Luo, Y., Liu, G., Yu, B.K.: ‘Experimental investigation of copper-grooved micro heat pipes (MHPs)’, J. Solid State Light., 2014, 1, (1), pp. 1–8 (doi: 10.1016/j.jssc.2014.04.008).
3. 3)
  - 10. Tang, Y., Lu, L.S., Deng, D.X., Yuan, D.: ‘Cold welding sealing of copper-water micro heat pipe ends’, Trans. Nonferr. Met. Soc. China, 2009, 19, (3), pp. 568–574 (doi: 10.1016/S1003-6326(08)60314-3).
4. 4)
  - 5. Tao, M., Lee, S.W.R., Yuen, M.M.F., Zhang, G.Q., van Driel, W.: ‘Effect of die attach adhesive defects on the junction temperature uniformity of LED chips’. 35th IEEE/CPMT Int. Electronic Manufacturing Technology Symp. (IEMT), 2012.
5. 5)
  - 12. Oshman, C.J., Shi, B., Li, C., Yang, R.G., Lee, Y.C., Bright, V.M.: ‘Fabrication and testing of a flat polymer micro heat pipe’. 15th Int. Conf. on Solid-State Sensors, Actuators and Microsystems Transducers 2009, 2009, pp. 1999–2002.
6. 6)
  - 11. Xiaowei, L., Chao, W., Luwen, W., Tian, H.: ‘Design and fabrication of flat heat pipes with different length’. Academic Int. Symp. on Optoelectronics and Microelectronics Technology (AISOMT), 2011, 2011.
7. 7)
  - 13. Singh Dhillon, N., Pisano, A.P.: ‘Enabling two-phase microfluidic thermal transport systems using a novel thermal-flux degassing and fluid charging approach’, J. Micromech. Microeng., 2014, 24, (3), p. 035021 (doi: 10.1088/0960-1317/24/3/035021).
8. 8)
  - 8. Suman, B.: ‘Modeling, experiment, and fabrication of micro-grooved heat pipes: an update’, Appl. Mech. Rev., 2007, 60, (3), p. 107 (doi: 10.1115/1.2730846).
9. 9)
  - 6. Siegal, B.S.: ‘Electrical transients simplify LED junction-temperature measurements’, Electro-Opt. Syst. Des., 1981, 13, (11), pp. 47–49.
10. 10)
  - 2. Tang, Y., Ding, X., Yu, B., Li, Z., Liu, B.: ‘A high power LED device with chips directly mounted on heat pipes’, Appl. Therm. Eng., 2014, 66, (1–2), pp. 632–639 (doi: 10.1016/j.applthermaleng.2014.02.067).
11. 11)
  - 16. Liu, Z., Wang, Z., Ma, C.: ‘An experimental study on heat transfer characteristics of heat pipe heat exchanger with latent heat storage. Part I: Charging only and discharging only modes’, Energy Convers. Manage., 2006, 47, (7–8), pp. 944–966 (doi: 10.1016/j.enconman.2005.06.004).
12. 12)
  - 19. Lu, X.Y., Hua, T.C., Liu, M.J., Cheng, Y.X.: ‘Thermal analysis of loop heat pipe used for high-power LED’, Thermochimica Acta, 2009, 493, (1–2), pp. 25–29 (doi: 10.1016/j.tca.2009.03.016).
13. 13)
  - 4. Zheng, H.D., Dong, L., Yin, X.K., et al: ‘Ppb-level Qepas No2 sensor by use of electrical modulation cancellation method with a high power blue LED’, Sens. Actuators B, Chem., 2015, 208, pp. 173–179 (doi: 10.1016/j.snb.2014.11.015).
14. 14)
  - 3. Rha, S.K., Lee, Y.S.: ‘Electroless Cu plating on anodized Al substrate for high power LED’, J. Nanosci. Nanotechnol., 2015, 15, (3), pp. 2422–2426 (doi: 10.1166/jnn.2015.10253).
15. 15)
  - 14. Launay, S., Sartre, V., Lallemand, M.: ‘Experimental study on silicon micro-heat pipe arrays’, Appl. Therm. Eng., 2004, 24, (2–3), pp. 233–243 (doi: 10.1016/j.applthermaleng.2003.08.003).
16. 16)
  - 7. Lock, D.A., Hall, S.R.G., Prins, A.D., Crutchley, B.G., Kynaston, S., Sweeney, S.J.: ‘LED junction temperature measurement using generated photocurrent’, J. Disp. Technol., 2013, 9, (5), pp. 396–401 (doi: 10.1109/JDT.2013.2251607).
17. 17)
  - 18. Li, Y., Li, P.F., Zeng, Z.X.: ‘Micro heat pipe cooling solution for high power LED illuminator’, Laser Optoelectron. Prog., 2010, 5, pp. 113–119.
18. 18)
  - 9. Liu, Y., Wang, H., Prasad, A.K., Advani, S.G.: ‘Role of heat pipes in improving the hydrogen charging rate in a metal hydride storage tank’, Int. J. Hydrog. Energy, 2014, 39, (20), pp. 10552–10563 (doi: 10.1016/j.ijhydene.2014.04.197).
19. 19)
  - 15. Yang, K.S., Cheng, Y.C., Jeng, M.S., Chien, K.H., Shyu, J.C.: ‘An experimental investigation of micro pulsating heat pipes’. 8th Annual IEEE Int. Conf. on Nano/Micro Engineered and Molecular Systems, 2013 (IEEE NEMS 2013), 2013, pp. 869–872.

Charging method of micro heat pipe for high-power light-emitting diode

References

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