Improving the cooling performance of automobile radiator with Al2O3/water nanofluid
Highlights
► Application of nanofluid in the car radiator has been studied experimentally. ► Heat transfer enhancement of about 45% compared to water has been recorded. ► Increasing particle concentration and velocity improves heat transfer performance.
Introduction
A reduction in energy consumption is possible by improving the performance of heat exchange systems and introducing various heat transfer enhancement techniques. Since the middle of the 1950s, some efforts have been done on the variation in geometry of heat exchanger apparatus using different fin types or various tube inserts or rough surface and the like [1], [2], [3], [4], [5], [6], [7]. Some of the published investigations have focused on electric or magnetic field application or vibration techniques [8], [9], [10], [11]. Even though an improvement in energy efficiency is possible from the topological and configuration points of view, much more is needed from the perspective of the heat transfer fluid. Further enhancement in heat transfer is always in demand, as the operational speed of these devices depends on the cooling rate. New technology and advanced fluids with greater potential to improve the flow and thermal characteristics are two options to enhance the heat transfer rate and the present article deals with the latter option.
Conventional fluids, such as refrigerants, water, engine oil, ethylene glycol, etc. have poor heat transfer performance and therefore high compactness and effectiveness of heat transfer systems are necessary to achieve the required heat transfer. Among the efforts for enhancement of heat transfer the application of additives to liquids is more noticeable. Recent advances in nanotechnology have allowed development of a new category of fluids termed nanofluids. Such fluids are liquid suspensions containing particles that are significantly smaller than 100 nm, and have a bulk solids thermal conductivity higher than the base liquids [12]. Nanofluids are formed by suspending metallic or non-metallic oxide nanoparticles in traditional heat transfer fluids. These so-called nanofluids display good thermal properties compared with fluids conventionally used for heat transfer and fluids containing particles on the micrometer scale [13]. Nanofluids are the new window which was opened recently and it was confirmed by several authors that these working fluid can enhance heat transfer performance.
Pak and Cho [14] presented an experimental investigation of the convective turbulent heat transfer characteristics of nanofluids (Al2O3–water) with 1–3 vol.%. The Nusselt number for the nanofluids increases with the increase of volume concentration and Reynolds number.
Wen and Ding [12] assessed the convective heat transfer of nanofluids in the entrance region under laminar flow conditions. Aqueous based nanofluids containing Al2O3 nanoparticles (27–56 nm; 0.6–1.6 vol.%) with sodium dodecyl benzene sulfonate (SDBS) as the dispersant, were tested under a constant heat flux boundary condition. For nanofluids containing 1.6 vol.%, the local heat transfer coefficient in the entrance region was found to be 41% higher than that of the base fluid at the same flow rate. Heris et al. [15] examined and proved the enhancement of in-tube laminar flow heat transfer of nanofluids (water–Al2O3) in a constant wall temperature boundary condition. In other work, Heris et al. [16] presented an investigation of the laminar flow convective heat transfer of Al2O3–water under constant wall temperature with 0.22.5 vol.% of nanoparticle for Reynolds number varying between 700 and 2050. The Nusselt number for the nanofluid was found to be greater than that of the base fluid; and the heat transfer coefficient increased with an increase in particle concentration. The ratio of the measured heat transfer coefficients increases with the Peclet number as well as nanoparticle concentrations.
Lai et al. [17] studied the flow behavior of nanofluids (Al2O3–water; 20 nm) in a millimeter-sized stainless steel test tube, subjected to constant wall heat flux and a low Reynolds number (Re < 270). The maximum Nusselt number enhancement of the nanofluid of 8% at the concentration of 1 vol.% was recorded. Jung et al. [18] conducted convective heat transfer experiments for a nanofluid (Al2O3–water) in a rectangular microchannel under laminar flow conditions. The convective heat transfer coefficient increased by more than 32% for 1.8 vol.% nanoparticle in the base fluids. The Nusselt number increased with an increasing Reynolds number in the laminar flow regime (5 < Re < 300) and a new convective heat transfer correlation for nanofluids in microchannels was also proposed.
Sharma et al. [19] implemented 12.5 vol.% Al2O3 in water in a horizontal tube geometry and concluded that at Pe number of 3500 and 6000 up to 41% promotion in heat transfer coefficient compared to pure water may be occurred. Ho et al. [20] conducted an experiment for cooling in horizontal tube in laminar flow of Al2O3–water at 1 and 2 vol.% concentration and concluded the interesting enhancement of 51% in heat transfer coefficient. Nguyen et al. [21] performed their experiments in the radiator type heat exchanger and at 6.8 vol.% Al2O3 in water obtained 40% increase in heat transfer coefficient.
Some extensive reviews in nanofluid heat transfer have also been published by Godson et al. [22], Kakaç and Pramuanjaroenkij [23] and Wang and Mujumdar [24]. The interested reader can refer to them for complete reviewing of the previous studies performed.
In this paper, forced convection heat transfer coefficients are reported for pure water and water/alumina nanopowder mixtures under fully turbulent conditions. The test section is made up with a typical automobile radiator, and the effects of the operating conditions on its heat transfer performance are analyzed.
Section snippets
Experimental rig
As shown in Fig. 1, the experimental system used in this research includes flow lines, a storage tank, a heater, a centrifugal pump, a flow meter, a forced draft fan and a cross flow heat exchanger (an automobile radiator). The pump gives a constant flow rate of 10 l/min; the flow rate to the test section is regulated by appropriate adjusting of a globe valve on the recycle line shown in Fig. 1. The working fluid fills 25% of the storage tank whose total volume is 30 l (height of 35 cm and
Nanofluid physical properties
By assuming that the nanoparticles are well dispersed within the base fluid, i.e. the particle concentration can be considered uniform throughout the system; the effective physical properties of the mixtures studied can be evaluated using some classical formulas as usually used for two phase fluids. These relations have been used to predict nanofluid physical properties like density, specific heat, viscosity and thermal conductivity at different temperatures and concentrations [14], [26], [27],
Calculation of heat transfer coefficient
To obtain heat transfer coefficient and corresponding Nusselt number, the following procedure has been performed. According to Newton’s cooling law:
Heat transfer rate can be calculated as follows:
Regarding the equality of Q in the above equations:In Eq. (7), Nu is average Nusselt number for the whole radiator, m is mass flow rate which is the product of density and volume flow rate of fluid, Cp is fluid specific heat
Pure water
Before conducting systematic experiments on the application of nanofluids in the radiator, some experimental runs with pure water were done in order to check the reliability and accuracy of the experimental setup. Fig. 5 shows experimental results for constant inlet temperature of 49 °C. As expected, the Nusselt number is seen to increase for increasing the Reynolds number.
Also, comparison was made between the experimental data and two well-known empirical correlations: one of them suggested by
Conclusion
In this article, experimental heat transfer coefficients in the automobile radiator have been measured with two distinct working liquids: pure water and water based nanofluid (small amount of Al2O3 nanoparticle in water) at different concentrations and temperatures and the following conclusions were made.
- 1.
The presence of Al2O3 nanoparticle in water can enhance the heat transfer rate of the automobile radiator. The degree of the heat transfer enhancement depends on the amount of nanoparticle
Acknowledgements
The authors gratefully acknowledge the financial support of this work provided by Bandar Imam Petrochemical Complex (BIPC) in Mahshahr, Iran.
References (32)
- et al.
A study on heat transfer enhancement using straight and twisted internal fin inserts
International Communications in Heat and Mass Transfer
(2006) Effect of coil-wire insert on heat transfer enhancement and pressure drop of the horizontal concentric tubes
International Communications in Heat and Mass Transfer
(2006)- et al.
Performance analysis of a heat exchanger having perforated square fins
Applied Thermal Engineering
(2008) - et al.
Experimental study on heat transfer enhancement of a helically baffled heat exchanger combined with three-dimensional finned tubes
Applied Thermal Engineering
(2004) - et al.
Heat-transfer enhancement in fin-and-tube heat exchanger with improved fin design
Applied Thermal Engineering
(2009) - et al.
Effect of rounded corners on the secondary flow of viscoelastic fluids through non-circular ducts
International Journal of Heat and Mass Transfer
(2006) - et al.
Laminar flow of non-Newtonian fluid in right triangular ducts
International Communications in Heat and Mass Transfer
(2003) - et al.
Flow-induced vibration analysis of conical rings used for heat transfer enhancement in heat exchangers
Applied Energy
(2004) - et al.
Effects of EHD on heat transfer enhancement and pressure drop during two-phase condensation of pure R-134a at high mass flux in a horizontal micro-fin tube
Experimental Thermal and Fluid Science
(2006) - et al.
The influence of fluid properties on electrohydrodynamic heat transfer enhancement in liquids under viscous and electrically dominated flow conditions
Experimental Thermal and Fluid Science
(2000)
Numerical analysis for heat transfer enhancement of a lithium flow under a transverse magnetic field
Fusion Engineering and Design
Experimental investigation into convective heat transfer of nanofluids at the entrance region under laminar flow conditions
International Journal of Heat and Mass Transfer
Estimation of heat transfer coefficient and friction factor in the transition flow with low volume concentration of Al2O3 nanofluid flowing in a circular tube and with twisted tape insert
International Communications in Heat and Mass Transfer
Heat transfer enhancement using Al2O3–water nanofluid for an electronic liquid cooling system
Applied Thermal Engineering
Enhancement of heat transfer using nanofluids—an overview
Renewable and Sustainable Energy Reviews
Review of convective heat transfer enhancement with nanofluids
International Journal of Heat and Mass Transfer
Cited by (297)
Intermittent spray cooling on rationally-designed hierarchical surfaces for enhanced evaporative heat transfer performance
2024, International Communications in Heat and Mass TransferImprovement methods for thermal backflow phenomenon in engine compartment blow-type air cooler module
2023, Case Studies in Thermal EngineeringANFIS based effectiveness and number of transfer units predictions of MWCNT/water nanofluids flow in a double pipe U-bend heat exchanger
2023, Case Studies in Thermal EngineeringIntensification of thermal efficiency of a cross-flow heat exchanger under turbulent flow conditions using CuFe<inf>2</inf>O<inf>4</inf>/water nanofluid
2023, International Journal of Thermal SciencesExperimental and numerical investigations on the melting behavior of Fe<inf>3</inf>O<inf>4</inf> nanoparticles composited paraffin wax in a cubic cavity under a magnetic-field
2023, International Journal of Thermal Sciences