## 1 Introduction  
The cooling of electronics, in particular integrated circuits, has recently become of particular importance [1]. Currently produced electronic devices move towards miniaturization. At the same time, the number of transistors placed in integrated circuits is constantly growing. This means an increase in thermal power and an increase in heat flux density [2]. As a result, the excessive temperature of electronic devices is the main cause of their failure. It is estimated that up to 55% of electronic device failures are caused by this [3]. This makes it necessary to use more and more efficient cooling systems for integrated circuits. In this way, the performance and reliability of electronic devices can be improved. Typically, cooling methods are divided into active and passive [1]. Passive systems basically use natural convection, whereas active cooling systems use forced convection. Therefore, active systems must be supplied with external energy to increase the heat dissipation capacity. Of course, active cooling systems generally perform better. According to [4], free convection cooling systems can be used for heat flux densities up to \(1.5\times 10^{3}\) W/m\({}^{2}\), forced air convection up to \(1.5\times 10^{4}\) W/m\({}^{2}\), and forced liquid convection up to \(1.0\times 10^{6}\) W/m\({}^{2}\). Therefore, most methods of cooling high-power electronic devices are developed based on active cooling. Another division of cooling methods is based on the contact of electronics with the coolant into methods with direct and indirect contact [1]. The simplest direct contact method is air cooling. It is used to cool low-power electronics [5]. Liquid may be used instead of air. In this case, the cooled electronic device is immersed in a cooling liquid. The method is called immersion cooling. The coolant used in this method should be characterized by good thermal conductivity, high specific heat, and very poor electrical conductivity [6]. Heat exchange can take place by free convection; however, proper forcing of the flow can improve the cooling efficiency by about 50%. The method is widely used to cool servers and data centers. Another method of direct contact is spray cooling. In this method, the droplets generated in the nozzle are directed to the surface of the cooled element. Droplets in contact with the surface absorb heat from it and evaporate. In this case, the latent heat of the phase change also increases the heat flux discharged from the surface of the cooled element, resulting in very high cooling efficiency [7]. That is why the spray method is one of the most effective cooling methods for high-power electronic devices. The evolution of spray cooling is droplet electrowetting cooling. The main advantages of electrowetting cooling include the fast response, hot spot cooling, and low energy consumption [8]. A method similar to spray cooling is jet impingement cooling. The main difference is that jet impingement cooling does not require droplet atomization [9]. Exemplary methods representing indirect contact coolant with the cooled element are methods using a heat pipe [10] or a vapor chamber [11]. Both methods are based on the use of the latent heat of the phase change. Heat is absorbed from the source, the cooled element, by evaporation of the coolant. Then, the steam is condensed in a condenser acting as a heat sink from which the heat is discharged to the outside. Heat pipes are used for one-dimensional heat transfer, while the evaporation chambers are used for two-dimensional heat transfer [1]. The solid-liquid phase change is also used to cool electronics. PCM (phase-change materials) are usually used in combination with other cooling techniques [12]. A very important method of indirect contact cooling is the use of microchannel heat sinks. This method was proposed by [PERSON] and [PERSON] for the first time in 1981 [13]. The method consists of the flow of the coolant through a series of parallel microchannels [14].