Abstract
This study presents a numerical investigation on the effect of the U-shaped flow routing plate to laminar mixed convection heat transfer from protruded heat sources at the side walls of a horizontal channel. The air was used as a cooling fluid and protruded heat sources were equipped as 4 × 8 rows into the rectangular channel with insulated walls. Numerical investigations are carried out for the plate width/channel width ratio (LP/W) of 3/20, 1/10, 1/20 and plate angles (α) of 0°, 30°, 60° at different Reynolds (Re), modified Grashof (Gr*) and Richardson (Ri) numbers. In the study, periodic plate placement was analyzed numerically and the effects of a plate placement array on heat transfer enhancement were investigated. The highest heat transfer enhancement (180%) was observed for the values of α = 30° LP/W = 3/20 at all the Re, Gr* and Ri number values. The predominance of natural convection increases the use of the flow routing plate effectiveness but causes a decrease in the heat transfer enhancement after a certain number of Ri. Therefore, the increase in natural convection needs to be controlled. Theoretical fan power (Nfan) requirements due to pressure loss are also investigated. Depending on the parameters used in the numerical study, as a result of the plate usage, the pressure losses increased according to the case without a plate. It is observed that the most important factor affecting the pressure loss was the Re number and this case indicated that the plate placement was more appropriate for low values of Re. The findings obtained during the numerical studies were presented in detail as graphics of the row averaged Nusselt number (Nurow ave.) and the heater temperatures, surface stream lines, and temperature contours.
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Abbreviations
- A :
-
Heat transfer area, m2
- A c :
-
Channel cross-sectional area, m2
- c p :
-
Specific heat at a constant pressure, kJ/kg K
- D H :
-
Channel hydraulic diameter, m
- g :
-
Gravitational acceleration, m/s2
- Gr:
-
Grashof number, Gr = (gβ(Ts − Tinlet)ave.DH3)/v2
- Gr*:
-
Modified Grashof number, Gr* = (gβ\(\dot{q}_{{_{{{\text{conv}}.{\text{ave}}.}} }}\)DH4)/kv2
- h :
-
Convection heat transfer coefficient, W/m2 K
- H :
-
Channel height, m
- k :
-
Thermal conductivity, W/m K
- L P :
-
Plate width, m
- \(\dot{m}\) :
-
Mass flow rate of air, kg/s
- N fan :
-
Theoretical fan power, W
- Nurow ave:
-
Row average Nusselt number, Nurow ave. = \(\dot{q}_{{_{{{\text{conv}}\;{\text{row}}\;{\text{ave}}}} }}\)DH/(k(Ts − Tinlet)row ave.))
- P :
-
Absolute air pressure, Pa
- P atm :
-
Absolute atmospheric pressure, Pa
- P c :
-
Channel perimeter, m
- \(\dot{q}_{{{\text{conv}}.}}\) :
-
Convection heat flux, W/m2
- Re:
-
Reynolds number, Re = (winletDH)/v
- Ri:
-
Richardson number, Ri = Gr/Re2
- T :
-
Fluid temperature, K
- T inlet :
-
Air inlet temperature, K
- T s :
-
Heater surface temperature, K
- u :
-
x component of air velocity, m/s
- v :
-
y component of air velocity, m/s
- w :
-
z component of air velocity, m/s
- w inlet :
-
Air inlet velocity, m/s
- W :
-
Channel width, m
- ρ :
-
Air density, kg/m3
- α :
-
Plate angle
- β :
-
Thermal expansion coefficient at a constant pressure, 1/K
- v :
-
Kinematic viscosity, m2/s
- μ :
-
Dynamic viscosity, kg/ms
References
Mudawar I (2000). Assessment of high-heat-flux thermal management schemes. In: Proceedings of 2000 Intersociety Conferance on Thermal and Thermomechanical Phenomena in Electronic Systems, IEEE, (2):1–20
Remsburg R (2000). Thermal design of electronic equipment. Vol. 10. CRC press, Boca Raton
Peterson GP, Ortega A (1990) Thermal control of electronic equipment and devices. Adv Heat Transf 20:181–314
Perng SW, Wu HW (2008) Numerical investigation of mixed convective heat transfer for unsteady turbulent flow over heated blocks in a horizontal channel. Int J Therm Sci 47(5):620–632
Korichi A, Oufer L, Polidori G (2009) Heat transfer enhancement in self-sustained oscillatory flow in a grooved channel with oblique plates. Int J Heat Mass Transf 52(5):1138–1148
Fu WS, Tong BH (2004) Numerical investigation of heat transfer characteristics of the heated blocks in the channel with a transversely oscillating cylinder. Int J Heat Mass Transf 47(2):341–351
Yang SJ (2002) A numerical investigation of heat transfer enhancement for electronic devices using an oscillating vortex generator. Numer Heat Transf Part A Appl 42(3):269–284
Davidson ASL (2001) Effect of inclined vortex generators on heat transfer enhancement in a three-dimensional channel. Numer Heat Transf Part A Appl 39(5):433–448
Sohankar A (2007) Heat transfer augmentation in a rectangular channel with a vee-shaped vortex generator. Int J Heat Fluid Flow 28(2):306–317
Beig SA, Mirzakhalili E, Kowsari F (2011) Investigation of optimal position of a vortex generator in a blocked channel for heat transfer enhancement of electronic chips. Int J Heat Mass Transf 54(19):4317–4324
Fu WS, Chen CJ, Wang YY, Huang Y (2012) Enhancement of mixed convection heat transfer in a three-dimensional horizontal channel flow by insertion of a moving block. Int Commun Heat Mass Transfer 39(1):66–71
Fu WS, Ke WW, Wang KN (2001) Laminar forced convection in a channel with a moving block. Int J Heat Mass Transf 44(13):2385–2394
Myrum TA, Qiu X, Acharya S (1993) Heat transfer enhancement in a ribbed duct using vortex generators. Int J Heat Mass Transf 36(14):3497–3508
Valencia A (1999) Heat transfer enhancement due to self-sustained oscillating transverse vortices in channels with periodically mounted rectangular bars. Int J Heat Mass Transf 42(11):2053–2062
Chompookham T, Thianpong C, Kwankaomeng S, Promvonge P (2010) Heat transfer augmentation in a wedge-ribbed channel using winglet vortex generators. Int Commun Heat Mass Transfer 37(2):163–169
Perng SW, Wu HW, Jue TC (2012) Numerical investigation of heat transfer enhancement on a porous vortex-generator applied to a block-heated channel. Int J Heat Mass Transf 55(11):3121–3137
Wu JM, Tao WQ (2008) Numerical study on laminar convection heat transfer in a rectangular channel with longitudinal vortex generator. Part A: verification of field synergy principle. Int J Heat Mass Transf 51(5):1179–1191
Min C, Qi C, Wang E, Tian L, Qin Y (2012) Numerical investigation of turbulent flow and heat transfer in a channel with novel longitudinal vortex generators. Int J Heat Mass Transf 55(23):7268–7277
Sripattanapipat S, Promvonge P (2009) Numerical analysis of laminar heat transfer in a channel with diamond-shaped baffles. Int Commun Heat Mass Transf 36(1):32–38
Oztop HF, Varol Y, Alnak DE (2009) Control of heat transfer and fluid flow using a triangular bar in heated blocks located in a channel. Int Commun Heat Mass Transf 36(8):878–885
Pirasaci T, Sivrioglu M (2011) Experimental investigation of laminar mixed convection heat transfer from arrays of protruded heat sources. Energy Convers Manag 52(5):2056–2063
Fluent A (2011) User’s and theory guides. ANSYS FLUENT Inc, Canonsburg
Dogan A, Sivrioglu M, Baskaya S (2006) Investigation of mixed convection heat transfer in a horizontal channel with discrete heat sources at the top and at the bottom. Int J Heat Mass Transf 49(15):2652–2662
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Technical Editor: Jose A. dos Reis Parise.
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Kurşun, B., Sivrioğlu, M. Heat transfer enhancement using U-shaped flow routing plates in cooling printed circuit boards. J Braz. Soc. Mech. Sci. Eng. 40, 13 (2018). https://doi.org/10.1007/s40430-017-0937-z
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DOI: https://doi.org/10.1007/s40430-017-0937-z