Development of microfluidic chip for dilation of slurry

  • PDF / 3,239,013 Bytes
  • 14 Pages / 595.276 x 790.866 pts Page_size
  • 14 Downloads / 243 Views

DOWNLOAD

REPORT


RESEARCH PAPER

Development of microfluidic chip for dilation of slurry Prasanth Kumar Gunipe1 · Arup Kumar Das1  Received: 27 May 2020 / Accepted: 5 September 2020 / Published online: 18 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract In this paper, we propose a novel design of channels for dilution of microfluidic samples having suspended particles without the use of a secondary buffer solution. The proposed design takes advantage of parallelization to augment the sample processing rate while maintaining a similar dilation performance. Seven different microchannel geometries are tested to identify the most efficient design. The dilation performance and service life have been substantially increased by using improvised design, in which microchannels are connected between headers, and a circular pillar array is provided at the inlet of the channel. Various parameters affecting the dilation performance are investigated, from which the critical parameters are found to be channel aspect ratio and flow Reynolds number. An empirical relation, which can estimate the output slurry concentration as a function of aspect ratio and flow Reynolds number, is proposed. Particle accumulation patterns inside the headers are reported, and factors affecting it are discussed. Further, a technique to increase microchannel service life is discussed. Keywords  Dilation · Grayscale intensity · Microfluidic design · Parallelization

1 Introduction Dilution of samples containing micro and nanoparticles at a faster rate with improved accuracy is a common requirement in chemical, environmental clean-up, mineral handling, and bio-medical applications (Reyes et al. 2002). For instance, diluting water-based slurries having high concentrations of unwanted suspended impurities has become a global need to meet the clean water demands in locations having scarcity or in situations of natural disasters such as floods. One can note that flow behaviour and problems in handling slurry are well addressed at the macro-level, while at the micro-level, slurry transport is still challenging. Especially in microreactors and micro heat sinks, dense slurry may demand increased pumping power and frequently lead to channel clogging. Also, the heat transfer performance of micro heat sinks (Kuravi et al. 2010) majorly depends on slurry concentration. As these slurries have micro/nanoparticles of high thermal conductivity, increasing their concentration may improve the heat * Arup Kumar Das [email protected] 1



Microfluidics Laboratory, Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, India

transfer performance but at the expense of pressure drop and channel clogging. Thus, neither high nor low, but one has to choose the optimal concentration of slurry, which will enhance the overall performance of the system. Preparing slurries of optimal concentration is not always possible, hence it is recommended to dilute the dense slurry to the required concentration level. In addi