Elastomer Surface Pressure Sensor and its Intergration to a 'Smart' surface for Active Flow Control

弹性体表面压力传感器及其与“智能”表面的集成以实现主动流量控制

• 批准号: EP/C535847/1
• 负责人: Jonathan Morrison
• 金额: $ 99.12万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FC535847%2F1
• 关键词: Elastomer; Surface; Pressure; Sensor; its

The no-slip condition between the surface of an aircraft and the air in which it flies is responsible not only for drag, but for the lift as well. An obvious potentially huge benefit to a carbon-based economy is the reduction in fuel consumption of aircraft, road vehicles and ships. The technological goal of doing this, together with many others, constitutes an important area of research called flow control and the same techniques used to reduce drag may also be used to help control aircraft by improving their stability and manoeuvrability, that is producing additional lift or thrust when it is needed. This is often done by delaying separation, that is, by preventing stall that could otherwise occur when an aircraft is flying slowly or when it is manoeuvring near the limits of its flight envelope. Another way of doing this could be by introducing small perturbations into the jet that provides the thrust so making it deflect or break up more quickly. Such control of an aircraft would be especially useful if it were unmanned. What we wish to do here is to take advantage of recent developments in materials called polymers (the most often used polymer is PVC or plastic) some of which possess piezoelectric properties. By piezoelectric, we mean that the polymer can be made to expand or compress by applying a voltage or charge, and correspondingly, produce charge when the polymer is compressed. These are also called electroactive polymers or EAPS. If the polymer has the right properties and is designed optimally, it can be used in a great many applications such as the in the body as an artificial muscle. Obviously the most important 'muscle' in the body is the heart which is of course involved in the flow of blood around the body.Our specific application is to take the idea of a dimple on a golf ball and use it as an actuator, as the basis of changing the properties of the boundary layer flow around more-or-less any type of body. Dimples are, in fact, very efficient vortex generators and we have started using dimples that are made of EAP so that the dimple consists of a diaphragm that pops up and down either in a cyclic (or harmonic) fashion, or can be made to do so when required, a so-called ondemand vortex generator. In this case, we would wish the dimple to produce a single vortex of known strength for as long or as short as we would wish, and this requires an understanding of the basic fluid behaviour so that a model may be implemented. This means we have to sense the properties of the boundary layer and we can do this by taking advantage of the piezoelectric behaviour of the EAP. Then the polymer not only has an array of dimples for controlling the boundary layer, but it also has an array of pressure sensors so that the surface pressure signal may used to control the dimples. We can even develop a 'smat all-polymer skin that is made up of separate EAP layers where individual layers can be designed specifically to sense the forces of the skin, or to be actuated as an on-demand dimple actuator. Then we would be able to sense the pressure on the surface and actuate at the same position. Initially, we hope to control boundary layer by open-loop control only. In this case, the measured pressure is only used to diagnose the effect of the dimples. However, much more complicated (and potentially much more beneficial) is closed-loop control, in which the measured pressures are used to determine when and where the dimples should be actuated. This would require a control model, that is a clear expectation of how we would wish the flow to be. Each model would be very dependent on a great many conditions, not least the type of flow.

飞机表面和飞行的空气之间的无滑动条件不仅是为了阻力，而且还负责升降机。对基于碳的经济来说，显而易见的可能是巨大的好处，这是飞机，公路车辆和船舶的燃油消耗减少。这样做的技术目标以及许多其他研究的重要领域称为流量控制，并且用于减少阻力的相同技术也可以用来通过提高其稳定性和可操作性来帮助控制飞机，这在需要时会产生额外的提升或推力。这通常是通过延迟分离来完成的，即防止在飞机缓慢飞行或在飞行信封范围附近操纵飞行时可能发生的摊位。这样做的另一种方法可能是将小型扰动引入喷气机，从而提供推力，从而使其偏转或更快地分解。如果飞机无人驾驶，对飞机的这种控制将特别有用。我们希望在这里做的是利用称为聚合物（最常使用的聚合物是PVC或塑料）的最新发展，其中一些具有压电性能。通过压电，我们的意思是，可以通过施加电压或电荷来使聚合物扩展或压缩，并在压缩聚合物时相应地产生电荷。这些也称为电活性聚合物或EAP。如果聚合物具有合适的特性并且最佳设计，则可以在许多应用中（例如人造肌肉）中使用。显然，人体中最重要的“肌肉”当然是在体内围绕血液流动的心脏。我们的特定应用是将高尔夫球块上的酒窝的想法带入高尔夫球，并将其用作执行器，作为改变边界层围绕任何或任何类型任何类型的任何类型的边界层流动的基础。实际上，酒窝是非常有效的涡旋发电机，我们已经开始使用由EAP制成的酒窝，因此Dimple由隔膜组成，它以环状（或谐波）方式上下弹出，或者可以在需要时做到的，即所谓的Ondemand vortex生成器。在这种情况下，我们希望Dimple能够在我们希望的那样长期或短时间产生已知强度的单个涡旋，这需要了解基本的流体行为，以便可以实现模型。这意味着我们必须感知边界层的特性，我们可以利用EAP的压电行为来做到这一点。然后，聚合物不仅具有用于控制边界层的一系列酒窝，而且还具有一系列压力传感器，因此表面压力信号可以用于控制凹痕。我们甚至可以开发一个由单独的EAP层组成的SMAT全聚合物皮肤，可以专门设计单个层以感知皮肤的力，或者将其作为按需的Dimple Actuator驱动。然后，我们将能够感觉到表面上的压力并处于相同位置。最初，我们希望仅通过开环控制控制边界层。在这种情况下，测得的压力仅用于诊断酒窝的作用。但是，更复杂的（可能更有益）是闭环控制，其中使用测量的压力来确定应在何时何地进行凹痕。这将需要一个控制模型，这清楚地期望我们希望流动如何。每个模型都将非常取决于许多条件，尤其是流动类型。

项目成果

Flow control with active dimples

通过主动凹坑进行流量控制

• DOI: 10.1017/s0001924000004887
• 发表时间: 2016
• 期刊: The Aeronautical Journal
• 作者: Dearing S

Modelling electro-active polymer (EAP) actuators: electromechanical coupling using finite element software.

电活性聚合物 (EAP) 执行器建模：使用有限元软件进行机电耦合。

• 发表时间: 2008
• 作者: Florence Rosenblatt

Electroactive polymers for flow control

用于流量控制的电活性聚合物

• 发表时间: 2006
• 作者: SS Dearing