SBIR Phase I: Electro-Mechanical Micro-Vibratory Transducers for Convective Heat Transfer Enhancement

该小型企业创新研究(SBIR)第一阶段项目专注于开发一种方法，以适应新型机电微振动换能器的使用，以增强热交换器中的对流换热速率，同时最大限度地减少任何额外的流动压降。换能器由非常薄、重量很轻的复合片组成，其中包含组合传感器和振动致动器，用于检测边界层流动条件并激励粘性壁层以控制边界层过渡和分离。这种创新的方法使用局部亚微米级别的壁面振动来增加壁面摩擦，同时减弱流动中的整体湍流水平。与传统形式的湍流强化换热相比，这有望降低流动压降的增加。换能器的功率消耗也比竞争最好的主动流量控制设备小约三个数量级，预计与传热率相比微不足道。这种换能器可以很容易地集成到热交换器空气侧的板片、翅片或管子上。商业上的可行性在于，它可以提高制造和加工工业中涉及气相干燥的废热回收和利用。它还可以使固定和车载供暖、通风和空调(HVAC)和发电系统更加紧凑和高效。它可以通过在较小的空间内促进散热来实现电子组件的更密集封装。

This Small Business Innovation Research (SBIR) Phase I project is focused on developing a method to adapt the use of a novel electro-mechanical micro-vibratory transducer to enhance convective heat transfer rates in heat exchangers while minimizing any added flow pressure drop. The transducer is composed of a very thin, light weight composite sheet that contains the combination sensors and vibratory actuators that are used to detect boundary layer flow conditions and to excite the viscous wall layer to control boundary layer transition and separation. The innovative approach uses localized sub-micron level wall vibrations to increase the wall skin friction while attenuating the overall turbulence level in the flow. This is expected to lower the flow pressure drop increase compared to traditional forms of heat transfer enhancement through turbulence enhancement. The power consumption of the transducer is also about three orders of magnitude smaller than the best competing active flow control devices and is expected to be insignificant in comparison to the heat transfer rates. The transducer can be easily integrated to plates, fins or tubes on the airside of a heat exchanger.The commercial viability is that it can improve waste heat recovery and utilization for manufacturing and processes industries involving gaseous phase drying. It can also make stationary and vehicle mounted heating ventilating and air-conditioning (HVAC) and power generation systems more compact and efficient. It can allow denser packaging of electronic components by facilitating heat dissipation in a smaller space.