## 1 Introduction  
The fast development of microelectronic devices requires advanced thermal management. For devices with large heat flux such as integrated circuits and concentrator solar cells, highly efficient heat transfer approaches are desired. One of the promising solutions that has gained much attention is thin film evaporation (TFE), which can accommodate large heat fluxes owing to liquid-to-vapor phase change. At the contact line between a wetting liquid and solid, there is a thin film region. When the film is ultra thin (usually on the order of 10 nm), the thermal resistance is very small. However, the intermolecular force between liquid and solid is very strong, thus almost no evaporation takes place. This region is called the adhesion film region. On the other hand, the film thickness is relatively large in the intrinsic meniscus region, which results in large thermal resistance and weak evaporation. Hence, most of the evaporation takes place in the region with relatively low thickness and low intermolecular forces. The schematic of evaporating thin film is demonstrated in Figure 1.  
Many researchers so far have conducted relevant studies through both theoretical analysis [1; 2; 3; 4]and experimental approaches [5; 6; 7]. From the theoretical point of view, it is troublesome to solve a sophisticated model that involves complicated partial differential equations. However, some assumptions should be made if a simplified problem is considered instead, which weakens the physical meaning. Since TFE is usually considered in micro-scale and even nano-scale devices, measuring the physical quantities, such as the thickness of liquid film and the local temperature, via experimental methods is also challenging. Besides, it is extremely difficult to go deep into the interfacial phenomena where evaporation takes place. Hence, it is imperative to investigate TFE using simulation approaches. Note that TFE is essentially a multiphase flow problem with heat transfer. There are many approaches that can be used in fluid flow simulations, such as the finite volume method [8], smoothed particle hydrodynamics [9], molecular dynamics (MD) [10], lattice Boltzmann method (LBM) [11], etc. Comparisons of various approaches can be found in [12; 13]. In our study of TFE, LBM is mainly considered, which is a mesoscopic computational fluid dynamics approach. It is known that LBM is good at tackling fluid-solid interaction and complex geometries. Besides, LBM employs a simple algorithm (collision and streaming), which makes it intrinsically scalable and parallelizable for computations. LBM has been used in many engineering and scientific problems, e.g., [14; 15; 16; 17; 18; 19; 20]. In this paper, we will show that LBM, and more specifically thermal LBM (TLBM), can reproduce several important phenomena in TFE, even without very fine mesh grids. Hence, it facilitates our understanding of the physics behind TFE and further device-level design. In the last decade, TLBM has been widely investigated [21]. There are several TLBM approaches, which can be classified as the multispeed method [22], the double distribution method [23], and the hybrid method [24]. A more detailed discussion of various approaches can be found in the excellent review paper [25]. It is noticed that TLBM has been applied in the study of many thermal flow problems, e.g., natural convection [26; 27], and boiling [28; 29; 30]. More recently, the authors of [31] reported results on TFE at a hydrophilic microstructured surface using a double distribution TLBM approach. The surface consists of micro pillars. The influence of wettability and heat flux on liquid film distribution and liquid-vapor interface morphology were investigated. In addition, the dependence of dry-out heat flux and wettability was discussed. In this paper, we also propose a double distribution TLBM approach that is based on a pseudo-potential function. The approach is considered in the study of TFE. We mainly focus on the interfacial phenomena, which may be hardly observed through experimental methods.