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More efficient electrochemical energy conversion through near-wall flow control

通过近壁流量控制实现更高效的电化学能量转换

基本信息

批准号：
239325001
负责人：
Professor Dr.-Ing. Christian Cierpka
金额：
--
依托单位：
Technische Thermodynamik
依托单位国家：
德国
项目类别：
Independent Junior Research Groups
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/239325001?language=en
关键词：
More efficient electrochemical energy conversion

项目摘要

The demand for energy is growing continuously due to the rising world population and the industrialization of emerging economies. An increasing part of this demand has to be produced using regenerative energy sources. Some of these sources, such as wind power and sunlight are not continuously available. Thus, the efficient energy storage is of great importance. Especially the electro chemical energy conversion in fuel cells or cells for electrolysis plays an important role. Since the reaction in these devices takes place at the electrodes surface, microfluidic solutions seem to be favourable. The surface can be largely increased by keeping the necessary volume small. The connection in series of plenty such microfluidic fuel cells can be used to establish the necessary power. The aim of the proposed project is to increase the efficiency of the electro chemical energy conversion by the application of near wall flow control and to understand the underlying physical phenomena in order to improve the design of future devices. Therefore measurements of the velocity field and scalar distributions of temperature, pH-value and pressure with high spatial and temporal resolution will be applied in single and multiphase micro flows. The proposed project focusses on the control of the near wall convection by the application of electromagnetic volume forces in multiphase systems and the flow control via passive secondary flows for single phase systems.One goal is the development of a microfluidic fuels cell in which the fuel and the oxidant flow next to each other without convective mixing. Therefore the expensive membrane of conventional fuel cell is not necessary. The efficiency of such a microfluidic fuel cell shall be enhanced using convection due to secondary flows which removes the depletion layer from the electrodes and refreshes the solution. Another goal is the investigation of the flow around single hydrogen bubbles produced on a macroscopic electrode mimicking a real electrolyser. Therefore highly resolved measurements of the velocity and the temperature will be performed with and without the application of Lorentz forces. Furthermore, a Marangoni convection was seen for the first time during water electrolysis on microelectrodes and further measurements on macroscopic electrodes on single hydrogen bubbles shall help to investigate if the origin of this phenomenon is related to temperature or concentration gradients.

由于世界人口的增加和新兴经济体的工业化，对能源的需求不断增长。越来越多的这种需求必须使用可再生能源来生产。其中一些能源，如风力和阳光，并不是持续可用的。因此，有效的能量存储是非常重要的。特别是电化学能量转换在燃料电池或电解电池中起着重要的作用。由于这些装置中的反应发生在电极表面，因此微流体溶液似乎是有利的。通过保持必要的小体积，可以大大增加表面。大量这种微流体燃料电池的串联连接可用于建立必要的电力。该项目的目的是通过应用近壁流动控制来提高电化学能量转换的效率，并了解潜在的物理现象，以改进未来设备的设计。因此，具有高空间和时间分辨率的速度场和温度、pH值和压力的标量分布的测量将应用于单相和多相微流。该项目的重点是通过在多相系统中应用电磁体积力来控制近壁对流，以及通过单相系统的被动二次流来控制流动，其中一个目标是开发一种微流体燃料电池，其中燃料和氧化剂彼此相邻流动而没有对流混合。因此，传统燃料电池的昂贵的膜是不必要的。这种微流体燃料电池的效率应使用由于二次流而产生的对流来增强，二次流从电极去除耗尽层并更新溶液。另一个目标是研究模拟真实的电解槽的宏观电极上产生的单个氢气泡周围的流动。因此，高分辨率的速度和温度的测量将进行与没有应用洛仑兹力。此外，Marangoni对流被认为是第一次在水电解过程中的微电极和宏观电极上的单个氢气泡的进一步测量将有助于调查，如果这种现象的起源是与温度或浓度梯度。