*2.2.3 Experimental set up*

**Figure 1** illustrates the heat sink used in the experimental setup [21]. **Figure 2** depicts the channel in the fabricated heat sink fitted with Four number of K-type thermocouples Thermocouples. The fabricated dimension of the heat sink comprising microchannels is tabulated in **Table 2**. Around 1 L of hybrid coolant is prepared and it is filled in the reservoir tank. It then flows to the test loop includes a needle valve in order to facilitate the different volumetric flow rates of synthesized hybrid nanocoolant. Omega rotameter (+1% full-scale accuracy) was used to measure the flow rate ranging from 0.35 to 0.75 LPM. The coolant enters the inlet port of the fabricated sink and absorbs the heat generated at the bottom of the sink due to its enhanced thermal properties and exits through the outlet port. This coolant is further cooled to its inlet temperature in a radiator as depicted in the cycle. **Figure 3** represents the fabricated heat sink made of copper with inlet


**111**

**Table 2.**

*Heat sink dimension mm.*

**Figure 1.**

**Figure 2.**

*Microchannel side view with thermocouples.*

**Various Fin parts Dimensions (mm)**

Width 55 Length 45 Height of fin 3 Width of microchannel 0.5 Heat sink base thickness 3

*Experimental flow diagram.*

*Analysis of Liquid Cooling in Microchannels Using Computational Fluid Dynamics (CFD)*

*DOI: http://dx.doi.org/10.5772/intechopen.96248*

#### **Table 1.**

*Thermo-physical properties of nano coolants at 303 K for volume fraction 0.1%.*

*Analysis of Liquid Cooling in Microchannels Using Computational Fluid Dynamics (CFD) DOI: http://dx.doi.org/10.5772/intechopen.96248*

**Figure 1.** *Experimental flow diagram.*

*Heat Transfer - Design, Experimentation and Applications*

enhancement of the thermal properties of nanofluid.

*2.2.1 Synthesis of graphene nanoparticle*

*2.2.2 Synthesis of iron oxide nanoparticle*

*2.2.3 Experimental set up*

**Coolant - type Density** 

**(kg/m3 )**

*Thermo-physical properties of nano coolants at 303 K for volume fraction 0.1%.*

of particles. Thus, it is required to synthesis a suspension of non-agglomerated and also well-monodispersed nanoparticles in the liquid are the key steps for the

To withstand the operating temperature it should high thermal stability

ii.Chemical compatibility and ease of chemical manipulation.

i.For the homogeneity of the medium, its dispersion should be uniform

Graphene oxide nanopowders are used for graphene synthesis. Quartz crucible filled with GO is kept inside the muffle furnace at 500 °C followed by the process of thermal exfoliation–reduction under air atmosphere for 4 min. The prepared graphene powder temperature is reduced to the air ambient temperature.

In 5 mL of distilled water, Iron (II) chloride tetrahydrate powder and 50 mL of isobutanol were added after which Fe2+ions were formed. The aqueous organic mixture was heated to 75 °C, added dropwise for 2 hours with 0.8 M NaOH and stirred for 30 min at 500 rpm. The synthesized iron oxide nanoparticles were washed with distilled water at 75 °C and dried in an oven at 50 °C. The dried particles of iron oxide nanoparticles were calcined for 2 h at 300 °C, 100 minutes at 400 and 600 °C. The hybrid nanofluid was prepared by dispersing the synthesized mono nanofluid in a volume fraction of 0.2 iron oxide with 0.8 fractions of graphene nanofluid to form graphene/iron oxide combination. The prepared hybrid fluid thermal properties as given in **Table 1** are used for further simulations.

**Figure 1** illustrates the heat sink used in the experimental setup [21]. **Figure 2** depicts the channel in the fabricated heat sink fitted with Four number of K-type thermocouples Thermocouples. The fabricated dimension of the heat sink comprising microchannels is tabulated in **Table 2**. Around 1 L of hybrid coolant is prepared and it is filled in the reservoir tank. It then flows to the test loop includes a needle valve in order to facilitate the different volumetric flow rates of synthesized hybrid nanocoolant. Omega rotameter (+1% full-scale accuracy) was used to measure the flow rate ranging from 0.35 to 0.75 LPM. The coolant enters the inlet port of the fabricated sink and absorbs the heat generated at the bottom of the sink due to its enhanced thermal properties and exits through the outlet port. This coolant is further cooled to its inlet temperature in a radiator as depicted in the cycle. **Figure 3** represents the fabricated heat sink made of copper with inlet

> **Specific heat (J/kg/K)**

G-Feo 1049.13 3795 1.209 1.4 De-ionisedwater 995.6 4178 0.615 1.0

**Thermal conductivity (W/mK)**

**Viscosity (cp)**

**110**

**Table 1.**

#### **Figure 2.**

*Microchannel side view with thermocouples.*


**Table 2.** *Heat sink dimension mm.*

**Figure 3.** *Microchannel with inlet and exit ports.*

and outlet ports. The average temperature of the four thermocouples indicates the experimentally measured base temperature of the heat sink.
