Islam Md Aminul, Rony Monoranjan Debnath, Hasan Mohammad Nasim
Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka, 1000, Bangladesh.
Heliyon. 2023 Apr 27;9(5):e15714. doi: 10.1016/j.heliyon.2023.e15714. eCollection 2023 May.
Surfaces with nano-pores have significant effect in enhancing heat transfer during phase change process. In this study, Molecular dynamics simulations have been performed to investigate thin film evaporation over different nano-porous substrate. The molecular system consists of argon as the working fluid and Platinum as the solid substrate. To study the effect of the nano-pores in phase change process, the nano-porous substrates had been structured with four different hexagonal porosity with three different heights. The structures of the hexagonal nano-pore were characterized through variation of void fraction as well as height to arm thickness ratio. Qualitative heat transfer performance has been characterized by closely monitoring the temporal variation of temperature and pressure, net evaporation number, wall heat flux of the system for all cases under consideration. The quantitative characterization of heat and mass transfer performance has been done by calculating the average heat flux and evaporative mass flux. Diffusion coefficient of argon is also evaluated to illustrate the effect of these nano-porous substrate in enhancing the movement of argon atoms thus heat transfer. It has been found that the presence of hexagonal nano-porous substrates significantly increases heat transfer performance. Structures with lower void fraction offers better enhancement of heat flux and other transport characteristics. Increment in nano-pores height also significantly enhances heat transfer. Present study clearly points out the noteworthy role associated with nano-porous substrate in modulating heat transfer characteristics during liquid-vapor phase change phenomena both from qualitative and quantitative perspectives.
具有纳米孔的表面在相变过程中对增强传热有显著影响。在本研究中，进行了分子动力学模拟以研究不同纳米多孔基底上的薄膜蒸发。分子系统由氩气作为工作流体和铂作为固体基底组成。为了研究纳米孔在相变过程中的作用，纳米多孔基底被构建为具有四种不同的六边形孔隙率和三种不同的高度。通过孔隙率以及高度与臂厚度比的变化来表征六边形纳米孔的结构。通过密切监测所有考虑情况下系统的温度和压力随时间的变化、净蒸发数、壁面热通量，对传热性能进行了定性表征。通过计算平均热通量和蒸发质量通量，对传热传质性能进行了定量表征。还评估了氩气的扩散系数，以说明这些纳米多孔基底在增强氩原子运动从而增强传热方面的作用。研究发现，六边形纳米多孔基底的存在显著提高了传热性能。孔隙率较低的结构能更好地增强热通量和其他传输特性。纳米孔高度的增加也显著增强了传热。本研究清楚地指出了纳米多孔基底在从定性和定量角度调节液 - 汽相变现象期间的传热特性方面所起的重要作用。
