The transfer of thermal energy is a core process in industrial processes. Improving the efficiency of heat exchangers could significantly reduce industrial energy consumption and costs. The thermo-hydraulic efficiency is widely used to evaluate heat exchanger efficiency. Dimples increase the thermo-hydraulic efficiency, but the performance of dimples under fouling conditions, and especially for particle-laden fluids, is inadequately investigated.

Experimental and numerical studies have shown that the application of dimples increases the turbulence near the wall, so that the heat transfer is increased, and deposited particles are detached from the wall. Here, the fluid-dynamic influence on particle transport is investigated by experimental determination of the three-dimensional velocity fields using stereoscopic micro particle image velocimetry (3D-µPIV) of a suspension in a flow channel. The influence of process parameters (flow velocity, particle concentration, dimple geometry) on turbulence, heat transfer and on particle deposition and removal is quantified.

The characteristic deposition pattern on dimpled surfaces is described by the adhesion and removal forces and is rated for different dimple geometries. With 3D-µPIV, the flow field inside the dimple is visualized and the formation of an oscillating vortex inside the dimple is proven experimentally. The existence of the vortex can explain the high heat transfer and the low fouling propensity of dimpled surfaces.

热能的传递是工业过程中的核心过程。提高热交换器的效率可以显着降低工业能耗和成本。热工效率被广泛用于评估热交换器的效率。酒窝提高了热工液压效率，但对结垢条件下酒窝的性能，尤其是对于载有颗粒的流体，还没有进行充分的研究。

实验和数值研究表明，凹痕的施加增加了壁附近的湍流，从而增加了热传递，并且沉积的颗粒从壁上脱离。在此，通过使用流动通道中悬浮液的立体微粒图像速度计（3D-µPIV），通过实验确定三维速度场，研究了流体动力学对颗粒传输的影响。量化了工艺参数（流速，颗粒浓度，凹坑几何形状）对湍流，传热以及对颗粒沉积和去除的影响。

凹陷表面上的典型沉积图案由附着力和去除力描述，并针对不同的凹窝几何形状进行了评级。使用3D-µPIV，可以看到酒窝内部的流场，并通过实验证明了酒窝内部振荡涡的形成。涡流的存在可以解释凹坑表面的高热传递和低结垢倾向。