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.

飞机表面和飞行空气之间的防滑状态不仅是阻力的原因，也是升力的原因。碳基经济的一个明显的潜在巨大好处是减少了飞机、公路车辆和轮船的燃料消耗。这样做的技术目标与许多其他技术目标一起，构成了一个称为流动控制的重要研究领域，用于减少阻力的相同技术也可以通过提高飞机的稳定性和机动性来帮助控制飞机，即在需要时产生额外的升力或推力。这通常是通过推迟分离来实现的，也就是防止飞机在飞行速度较慢或在接近飞行包线极限时出现失速。另一种方法是在喷流中引入微小的扰动，提供推力，使其更快地偏转或解体。如果飞机是无人驾驶的，这种控制将特别有用。我们在这里想要做的是利用聚合物材料(最常用的聚合物是聚氯乙烯或塑料)的最新发展，其中一些具有压电性能。我们所说的压电性是指通过施加电压或电荷使聚合物膨胀或压缩，相应地，当聚合物被压缩时产生电荷。这些也被称为电活性聚合物或EAP。如果聚合物具有合适的性能并经过优化设计，它可以用于许多应用，例如作为人造肌肉在人体内的应用。显然，人体中最重要的“肌肉”是心脏，心脏当然参与了身体周围的血液流动。我们的具体应用是将高尔夫球上的酒窝作为致动器，作为改变或多或少任何类型身体周围流动的边界层特性的基础。事实上，酒窝是非常有效的涡流发生器，我们已经开始使用由EAP制成的酒窝，因此酒窝由一个膜片组成，它以循环(或谐波)的方式上下弹出，或者在需要时可以这样做，即所谓的按需涡流发生器。在这种情况下，我们希望酒窝产生一个已知强度的单一涡旋，时间长短都可以，这需要了解基本的流体行为，以便可以实施模型。这意味着我们必须感知边界层的性质，我们可以通过利用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凹陷阵列，而且还具有压力传感器阵列，以便可以使用表面压力信号来控制凹陷。我们甚至可以开发一种由单独的EAP层组成的SMAT全聚合物皮肤，其中的各个层可以专门设计来感应皮肤的力，或者作为按需驱动的酒窝致动器。然后我们将能够感觉到表面上的压力，并在相同的位置上驱动。最初，我们只希望通过开环控制来控制边界层。在这种情况下，测量的压力仅用于诊断凹陷的影响。然而，更复杂(也可能更有益)的是闭环控制，在这种控制中，测量的压力被用来确定何时何地应该启动酒窝。这将需要一个控制模型，这是对我们希望的流程的明确预期。每个模型都非常依赖于许多条件，尤其是流动的类型。

项目成果

Investigation of Active Dimple Actuators for Separation Control

• DOI: 10.2514/6.2006-3190
• 发表时间: 2006-06
• 作者: Natalie Udovidchik;J. Morrison

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

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

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