**1. Introduction**

Thermal management of electronic components is the major concern to make the efficient high powered energy system [1–3]. The modern researchers' attention is on the development of efficient heat exchanging devices for thermal management of electronic components [4, 5]. Miniaturization has a noticeable footprint on heat exchanger technology and which makes the heat exchangers as compact and efficient. The life and overall efficiency of a thermal energy system are highly affected by its heat exchanger's efficiency. The microchannel heat sink is an inventive and highly compact heat dissipating device, so it is the most suitable for the application of thermal management of electronics. The performance and the life span of the electronic component with high power density is highly dependent on its heat dissipation capacity [6]. The performance of an electronic component is enhanced


#### **Table 1.**

*The classification of the mini and microchannels.*

**Figure 1.**

*The increment of studies performed on the micro-channels from the year 1996 to 2019 [15].*

by providing an efficient heat absorbing device like MCHS. The MCHS is also used in many other applications like LED cooling, fuel cells, refrigeration, combustors, chemical industry and food industry, etc. Huge literature availability on MCHS indicates the capacity of this technology.

The categorization of the microscale channels is different from the conventional flow channels, and it is done by considering the channel's hydraulic diameter. So many classifications are available from the literature. Many authors followed the classification given by S.G. Kandlikar and W.J. Grande [7] and S.S. Mehendale et al. [8], which is produced in **Table 1**.

The microchannel heat sink was first developed in 1981 for electronic cooling applications, which has rectangular cross-sectional channels made of silicon. In this study, the maximum thermal resistance of 0.09 0C/W was observed at the heat flux of 790 W/cm2 over the 1 cm2 area [9]. Since then, noticeable work has been done to improve the micro-channels' fluid flow and heat transfer performance by improving the channel geometry, surface roughness of the channel, channel aspect ratio, working fluid and substrate materials, etc. The thermal resistance of 0.070 C/W was achieved for the MCHS developed for thermal management of the diode laser array manufactured by Indium phosphide (InP) [10]. The hydraulic diameter and aspect ratio of the channel was proved to be has a noticeable impact on the thermal and hydraulic behavior of the M [11].

Initially, few studies claimed that the conventional correlations and theories are not applicable for the micro and mini channels. Eventually, researchers cleared about these ambiguities and concluded that the inaccuracies in the microchannel dimensional measurements are the main reason for the deviation of the results produced from the conventional correlations. The uncertainties in experiments

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**Figure 2.**

*Recent Advancements in Thermal Performance Enhancement in Microchannel Heatsinks…*

were proved to be dominated by the uncertainties in the diameter measurement, which may cause the 20% deviation in the measurement of Poiseuille's number [12]**.** In this analysis, fRe (Poiseuille's number) data for microscale stroke flow showed negligible deviation from the macroscale stroke flow. 3% uncertainty in the channel width and channel height leads to the 21% uncertainty in calculating the friction factor [13]. The electric double-layer effect, entrance effect, and entrance effect are also possible causes for the deviation of pressure drop, apart from the measurements' errors. To find the possible inaccuracies and partial thermal in the MCHS, enhanced thermal characterization methods were developed [14]. **Figure 1** represents the increment of studies performed on the micro-channels from the year

The heat sink is a heat-absorbing device that takes heat from its surroundings by the various modes of heat transfer by using working fluids. Miniaturization makes the heat sinks as efficient and compact. MCHSs have fluid flow channels in the size of microns. MCHS application is found in the high-powered density energy system with less space availability. These applications include the computer components cooling (Storage devices, CPUs and GPUs, etc.) [16], thermal management of high power density electronic components (IGBTs) [17], cooling of fuel cells [18], diode laser arrays [19], and combustors [20], etc. Electronic cooling is the major application of the MCHS. **Figure 2** represents the schematic diagram of the

Fabrication of MCHS is the biggest hurdle to perform the experimental investigations. Laser cutting [22], dry and wet etching [23–25], micro-cutting [26], and ultrasonic micro-machining [27] are very expensive fabrication methods for MCHS. Most of the researcher's attention is on developing a new low-cost manufacturing method with good surface characteristics. Kaikan Diao, Yuyuan Zhao [28] studied the performance of the sintered Copper microchannel manufactured by a low-cost fabrication method. This study proved that the pressure drop in the sintered copper microchannel was higher than the microchannel machined conventionally and noticeably lower than the porous Copper microchannel fabricated by the Lost carbonate sintering method (LCS). Ivel L. Collins et al. [29] performed the direct-metal-laser-sintering

*DOI: http://dx.doi.org/10.5772/intechopen.97087*

**2. Microchannel heatsink (MCHS)**

transistor with a liquid-cooled heat sink.

*Schematic diagram of the transistor with liquid-cooled heatsink [21].*

1996 to 2019 [15].

*Recent Advancements in Thermal Performance Enhancement in Microchannel Heatsinks… DOI: http://dx.doi.org/10.5772/intechopen.97087*

were proved to be dominated by the uncertainties in the diameter measurement, which may cause the 20% deviation in the measurement of Poiseuille's number [12]**.** In this analysis, fRe (Poiseuille's number) data for microscale stroke flow showed negligible deviation from the macroscale stroke flow. 3% uncertainty in the channel width and channel height leads to the 21% uncertainty in calculating the friction factor [13]. The electric double-layer effect, entrance effect, and entrance effect are also possible causes for the deviation of pressure drop, apart from the measurements' errors. To find the possible inaccuracies and partial thermal in the MCHS, enhanced thermal characterization methods were developed [14]. **Figure 1** represents the increment of studies performed on the micro-channels from the year 1996 to 2019 [15].
