## 3 Results  
In this work, we focus on simulations of heat transport in microchannels to study the behavior of this process and to investigate the effects of various design parameters on overall system performance. In this chapter, we present the results of our simulations, including the key observations and trends we identified, as well as the implications of our results for potential applications in various fields. Figure 4 presents streamlines for the most complex shape calculated, the channel with segment number n = 16. At the location where the streamline encounters a change in direction, such as a bend or, in this case, a corner, the fluid may experience local reversed flow due to the differences in fluid velocity and pressure between the inner and outer walls of the bend. This can cause the fluid to separate from the wall and form eddies, which can be seen in the calculated streamline as regions where the flow direction changes abruptly or where the streamline curves back on itself. The size and shape of the eddies depend on factors such as the curvature of the bend, the speed of the fluid, and the viscosity of the fluid. One of the significant flow parameters is the pressure drop, presented in Figure 5. The calculated data presented suggested that as the inlet velocity increases, there is an increase in pressure drop across the microchannel, which is consistent with the principle of fluid mechanics that the pressure drop in a channel is directly proportional to the velocity of the fluid. Additionally, while the data indicate that an increase in the bottom temperature of the microchannel corresponds to a decrease in pressure drop, this effect appears to be marginal when compared to the more pronounced influence of fluid velocity on the pressure dynamics within the microchannel. This implies that the thermal properties of the fluid and the channel have an important impact on the pressure drop. Furthermore, the data suggest that the effect of inlet velocity on the pressure drop is more pronounced than the effect of the bottom temperature. The more complex the shape of the channel, the higher is the pressure drop, again as expected by fluid flow principles. Figure 4: Streamlines for channel n = 16. The results presented in Figure 6 show that the hydraulic power in the microchannel is a function of both the inlet velocity and the bottom temperature. As the inlet velocity increases, the hydraulic power also increases, which is expected, as higher velocity results in greater fluid flow. On the contrary, as the bottom temperature increases, the hydraulic power decreases, which is related to the decrease in viscosity and density of the fluid. It can also be observed that higher velocities lead to an increased rate of rise in hydraulic power, although the effect of temperature on this increase is relatively marginal. The more complex the channel design, the more power that is required also increases. These results can provide insight into the optimization of microchannel heat transfer systems, such as determining the appropriate flow and temperature conditions to predict the required hydraulic power levels. The Darcy friction factor is presented in Figure 7, showing that its value decreases as the inlet velocity increases, while the effect of increasing heating bottom temperature is observed to be comparatively marginal. This result illustrates the fact that there is an intermediate relationship between the heating temperature and resistance. It can be seen that higher velocities lead to a decreased resistance to flow through the microchannel. It is also noticeable that the effect of the inlet velocity on the Darcy coefficient is more significant than the effect of the heating bottom temperature. This can be observed by comparing the values of the Darcy coefficient for different inlet velocities at the same heating bottom temperature. Also, it is visible that a higher number of zigzags results in higher friction factor values.