Experimental Studies on Automotive Radiator Performance using Water and Al2O3 Nanofluid

Experimental Studies on Automotive Radiator Performance using Water and Al2O3 Nanofluid

P. Sai Sasank1

1PG student, Thermal engineering, Siddharth institute of engineering and technology,

Puttur-517583

V. Govinda Naik 2

2Associate professor,Mechanical Engineering,

Siddharth institute of engineering and technology, Puttur-517583

Abstract—–The nano fluids have emerged as a new generation of heat transfer fluids attracted the attention of researchers over the past few years. Applications are chemical plants, automotive cooling, building heating, etc. Nanofluid is a new class of heat transfer fluid engineered by dispersing metallic or non metallic nanoparticles.

The nano fluids like Al2O3, SiC,CuO,TiO2 are the very commonly used in thermal systems and heat exchangers. An experimental study of performance of Al2O3 nano fluid in a car radiator was studied in the present work. Nanofluid was tested in a car radiator by varying the percentage of nanoparticles mix with the water.

Pure water is used in a radiator and its performance was studied. Al2O3 nano particles are mixed in water in 0.025%, 0.05% and 0.1% volume concentration and the performance was studied. The performance comparison has made between pure water and nanofluid tested in a radiator.

1. INTRODUCTION TO NANOFLUIDS

   Heat transfer fluids such as water, minerals oil and ethylene glycol play an important role in many industrial sectors including power generation, chemical production, air-conditioning, transportation and microelectronics. The use of nanofluids is one of the most effective mechanisms of increasing the amount of heat transfer in heat exchangers. The subject of the present paper is combining of the two mentioned methods for increase of heat transfer and parametric study of thermal and hydrodynamic performances of flow field.

2. THE CHARACTERISTIC FEATURES OF THE NANOFLUIDS INCLUDE:

1. Significant increase in the thermal conductivity with low volume concentrations.

2. Stronger dependence of thermal conductivity on temperature than the base-fluid alone.

3. Increased critical heat flux for pool boiling scenarios.

4. Substantial increase in heat transfer coefficient. TYPES OF NANOFLUIDS

Some nanoparticle materials that have been used in nanofluids are oxide ceramics (Al2O3, CuO, Cu2O), nitride ceramics (AIN, SiN), carbide ceramics (Sic, TiC), metals (Ag, Au, Cu, Fe), semiconductors (TiO2), single, double or multi-walled carbon (SWCNT, DWCNT, NWCNT), and composite materials such as nanoparticle core-polymer shell composites. In addition new materials

and structures are attractive for use in nanofluids where the particle-liquid interface is doped with various molecules.

The base fluids which are used in nanofluids are common heat transfer fluids such as water, engine oil, Ethylene glycol and ethanol.

Generally in the most researches, the following three kinds of nanoparticles were considered as the solid phase of nanofluid:

1. CuO and Cu2O Base Nanofluids:

   Cu2O is a p-type semiconductor that has received appreciable attentions recently due to its potential applications in fields such as solar cells, pigments, and catalysts. Nanoscaled Cu2O is expected to possess improved properties than its bulk one. Although Cu2O nanocrystals have been successfully synthesized by different methods, few approaches to synthesize shape- controlled Cu2O nanocrystals at mild conditions have been reported. Xiaohao Wei et al. indicated that Cu2O nanofluids can be synthesized by using the chemical solution method (CSM). The nanoparticle can be varied from a spherical shape to an octahedral one by adjusting some synthesis parameters. The nanofluid thermal conductivity can also be controlled by either the synthesis parameters or its temperature. The reaction between cupric-sulfate (CuSO4) and sodium-hydrate (NaOH) yields cupric-hydroxide (Cu (OH)2) and sodium-sulfate (Na2SO4).

2. Al and Al2O3 Base Nanofluids:

   Comparing micron-sized and Nano-sized alumina particles, Nano-alumina has many advantages. A smaller particle size would provide a much larger surface area for molecular collisions and therefore increase the rate of reaction, making it a better catalyst and reactant. Finer abrasive grains would enable finer polishing, and this would also give rise to new applications areas like nano- machining and nano-probes. In terms of coatings, the use of nano-sized alumina particles would significantly increase the quality and reproducibility of these coatings.

   There are several methods to synthesize nano-alumina, and these are categorized into physical and chemical methods. Physical methods include mechanical milling, laser ablation, flame spray and thermal decomposition in plasma. Chemical methods include solgel processing, solution combustion decomposition and vapor deposition. Most of

   the chemical methods have resulted in extremely low yield rates, and thus cannot be adapted to mass manufacturing.

   Physical methods like mechanical milling are not efficient as the size of the nanoparticles cannot be easily controlled, and these methods are only limited to certain materials. Other methods such as laser ablation, vapor deposition and sol-gel are very costly as they require specialized equipment such as vacuum systems, high power lasers as well as expensive precursor chemicals. Finally, most systems are only possible for a specific range of materials.

3. TiO2 Base Nanofluids:

Titanium dioxide (TiO2) is a very useful semiconducting transition metal oxide material and exhibits unique characteristics such as low cost, easy handling and non toxicity, and resistance to photochemical and chemical erosion. The properties of TiO2 are significantly dependent on the crystalline phase, i.e. anatase, rutile, or brookite.

LITERATURE REVIEW

In this section, the works done by various authorshave been reported as a literature review.

[1] M. Ebrahimi et al. (2014) Effect of adding SiO2 nanoparticle to base fluid (water) in car radiator is investigated experimentally. Effects of fluid inlet temperature, the flow rate and nanoparticle volume fraction on heat transfer are considered. Results show that Nusselt number increases with increase of liquid inlet temperature, nanoparticle volume fraction and Reynolds number.

[2]M. Naraki et al. (2013) In this research, the overall heat transfer coefficient of CuO/water nanofluid is investigated experimentally under laminar flow regime in a car radiator. The results show that the overall heat transfer coefficient with nanofluid is more than a base fluid. The overall heat transfer coefficient increases with the enhancement in the nanofluid concentration from 0 to 0.4 vol. %. Conversely, the overall heat coefficient decreases with increasing the nanofluid inlet temperature from 50 to 80ºC. The implementation of nanofluid increases the overall heat transfer coefficient up to 8% at nanofluid concentration of 0.4 vol. % in coefficient with nanofluid, effect on each operating parameter on overall heat transfer coefficient and the optimum values of each parameter are determined.

1. S. M. Peyghambarzadeh et al. (2012) The heat transfer performance of the automobile radiator is evaluated experimentally by calculating the overall heat transfer coefficient according to the conventional -NTU technique. The effects of these variables on the overall heat transfer coefficient are deeply investigated. Results demonstrate that both nanofluids show greater oveall heat transfer coefficient in comparison with water up to 9%. Furthermore, increasing the nanoparticle concentration, air velocity and the nanofluid velocity enhances the overall heat transfer coefficient. In contrast, increasing the nanofluid inlet temperature, lower overall heat transfer coefficient was recorded.

   SCOPE OF PRESENT WORK

   In this, forced convection heat transfer coefficients are reported for pure water and water/Al2O3 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 at different flow rates and at different inlet temperatures. The Nusselt number, Reynolds number and friction factor are also estimated.

   ANALYSIS OF AL2O3 NANOPARTICLES

   Product Name	Alumina Powder Nano Grade
   Color	White
   CrystalForm	Alpha
   PH Value	6.6
   SSA, m2/g	15
   Particle Size	20nm
   Al2O3 Content	99.99%
   Si	10.8 ppm
   Na	9.01 ppm
   K	10.6 ppm
   Fe	9.75 ppm
   Cu	0.12 ppm
   Ti	0.86 ppm
   Mn	0.72 ppm

   EXPERIMENTAL SETUP OF AUTOMOTIVE RADIATOR

   EFFECT OF REYNOLDS NUMBER ON HEAT TRANSFER ENHANCEMENT

   14

   Figure 1: Schematic diagram of test setup

   FORMULAE

   1. Heat transfer coefficient Q = h ×As (Tb-Tw)

   2. Heat transfer rate

      Q = m Cp T = m Cp (Tin-Tout)

   3. Nusselt Number

      Nu =0.332×Re0.5 ×Pr0.33

   4. Reynolds Number Re =

   5. Friction factor

      f = (0.79 lnRe-1.69)-2

   6. Volume concentration of Nanoparticle %

      volume concentration =

      12

      Heat transfer enhancement (%)

      0.025% nanofluid

      0.05% nanofluid

      10 0.1% nanofluid

      8

      6

      4

      2

      0

      0 200 400 600 800 1000 1200 1400

      Reynolds number (Re)

      Figure a: Effects of the Reynolds number on heat transfer enhancement at 60º

      14

      Heat transfer enhancement (%)

      12

      0.025% nanofluid

      0.05% nanofluid

      10 0.1% nanofluid

      8

      +

   7. Density of nanofluidnf = (1-)f + p 6

   8. Thermal conductivity of nanofluid knf =kf kp +2kf +2(kp kf )

      kp +2kf (kp kf )

   9. Viscosity

      nf = (1+2.5)w

   10. Heat capacity of nanofluid

       Cpnf = 1 Cp f f +Cp p p

       nf

   11. Heat transfer enhancement E = Nu nf Nu f

Nu f

4

2

0

0 200 400 600 800 1000 1200 1400 1600

Reynolds number (Re)

Figure .b: Effects of the Reynolds number on heat transfer enhancement at 70ºC

14

Heat transfer enhancement (%)

12

0.025% nanofluid

0.05% nanofluid

10 0.1% nanofluid

RESULTS AND DISSCUSSION

The experiments are conducted on fabricated model of experimental setup by using water as base fluid, 0.025%, 0.05%, 0.1% nanofluids as test fluids. The obtained results are recorded. The parameters like Nusselt number (Nu), Reynolds number (Re), friction factor, heat transfer enhancement are recorded and shown graphically below

8

6

4

2

0

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Reynolds number (Re)

Figure .c: Effects of the Reynolds number on heat transfer enhancement at 80ºC

. The enhancement in heat transfer has increased by augmentation in the concentrations of nanoparticle, Improvement in the heat transfer rate when = 0.1% and the E value is about 4.56% for 0.025% Al2O3 nanofluid at 80ºC and this value is about 12.4% for 0.1% Al2O3 nanofluid at 80ºC

CONCLUSION.

The convective heat transfer performance and flow characteristics of Al2O3 nanofluid flowing in an automotive radiator have been experimentally investigated. Significant increase in heat transfer was observed with the used different volume concentrations of nanoparticles mixed with water.

The experimental results have shown that the heat transfer enhancement was about 4.56% for 0.025% Al2O3 nanofluid at 80ºC and this is about 12.4% for 0.1% Al2O3 nanofluid at 80ºC.The results have shown that Al2O3 nanofluid has a high potential for hydrodynamic flow and heat transfer enhancement in an automotive radiator.

SCOPE OF FUTURE WORK

Experiments can be further carried out with higher particle concentrations for measurement of heat transfer coefficients. Experiments can also be extended for different base fluids e.g. transformer oil, ethylene glycol etc for investigation of heat transfer characteristics. Carbon nanotubes (CNT) have very high thermal conductivity about 3000 w/m K. So, CNT/water nanofluid can be studied with different surfactants at various particle concentrations. Limited work has been reported on the cooling applications of nanofluid using carbon nanotubes (CNT).

REFERENCES

1. 1. M. Ebrahimi, M.Farhadi, K.Sedighi, S.Akbarzade Experimental investigation of force convection heat transfer in a car radiator filled with SiO2-water nanofluid, IJE TRANSACTIONS B: Applications Vol. 27, No. 2, (February 2014) 333-340.

2. 2.Vlassov, V. V., de Sousa, F. L. and Takahashi, W. K., "Comprehensive optimization of a heat pipe radiator assembly filled with ammonia or acetone", International Journal of Heat and Mass Transfer , Vol. 49, No. 23, (2006), 4584-4595.

3. 3. Adnan M. Hussein, R.A. Bakar, K. Kadirgama Study of forced convection nanofluid heat transfer in the automotive cooling system, case studies in Thermal Engineering 2 (2014) 50-61.

4. 4. Pantzali, M., Mouza, A. and Paras, S., "Investigating the efficacy of nanofluids as coolants in plate heat exchangers (PHE)", Chemical Engineering Science , Vol. 64, No. 14, (2009), 3290-3300.

5. 5. Kakaç, S. and Pramuanjaroenkij, A., "Review of convective heat transfer enhancement with nanofluids", International Journal of Heat and Mass Transfer , Vol. 52, No. 13, (2009), 3187- 3196.

6. 6. Leong, K., Saidur, R., Kazi, S. and Mamun, A., "Performance investigation of an automotive car radiator operated with nanofluid- based coolants (nanofluid as a coolant in a radiator)", Applied Thermal Engineering , Vol. 30, No. 17, (2010), 2685- 2692.

7. 7. Naraki, M., Peyghambarzadeh, S., Hashemabadi, S. and Vermahmoudi, Y., "Parametric study of overall heat transfer coefficient of CuO/water nanofluids in a car radiator", International Journal of Thermal Sciences, (2013).

8. 8. Vajjha, R. S., Das, D. K. and Namburu, P. K., "Numerical study of fluid dynamic and heat transfer performance of Al2O3 and CuO nanofluids in the flat tubes of a radiator", International Journal of Heat and Fluid Flow , Vol. 31, No. 4, (2010), 613-621.

9. 9. Lai, W., Duculescu, B., Phelan, P. and Prasher, R., "Convective heat transfer with nanofluids in a single 1.02-mm tube", ASME. (2006).

10. 10. Peyghambarzadeh, S., Hashemabadi, S., Hoseini, S. and Seifi Jamnani, M., "Experimental study of heat transfer enhancement using water/ethylene glycol based nanofluids as a new coolant for car radiators", International Communications in Heat and Mass Transfer , Vol. 38, No. 9, (2011), 1283-1290.