Deterministic ratchets for suspension fractionation

摘要: Driven by the current insights in sustainability and technological development biorefining natural renewable resources, food industry has taken an interest fractionation of agrofood materials, like milk cereal crops. The purpose is to split raw material several functional ingredients. For example, can be fractions containing fat, casein micelles, whey proteins. Traditionally, separation processes are mainly aimed at separating fluid from a suspension stream. Frequently membrane technology used this type separation; membranes seem obvious choice because they able sieve components during mild many foods, which suspensions nature, milk, or suspended liquid processing (such as starch granule suspensions). However, hindered fouling pores ingredients accumulation these front pore, makes with more challenging than plain solids. That why we have investigated possibilities alternative technologies such microfluidic devices, evaluated them under conditions required for applications. Microfluidic devices currently biological applications, sorting DNA cells. Due large degree freedom design, very suited innovative technologies. First, various designs available literature chapter 2, concludes that so-called deterministic ratchets most promising suspensions. This conclusion based on high yield, compactness equipment, selectivity reached devices. In chapters 3 6, report detailed investigations through 2D simulation (chapter 3), image analysis comparison results 4), full 3D simulations combination previously mentioned methods 5). last chapter, our findings summarized classification design rules, outlook future developments given. Deterministic microchannels, regularly spaced array obstacles, particle flows. essential property each obstacle row displaced slightly laterally respect previous row. Small particles follow streamlines fluid, zigzag around while larger certain critical size bump into consequently their streamline. will continuously direction obstacles placed, angle flow direction. small moving flow, implies zero degrees. Via difference migration displacement motion, fractionated, collected different outlets. An important relative width lane, determines whether it show motion not. intensively means 2-D field simulation. related lanes, within zigzagging move, determined lane widths designs. distribution found depend strongly ratchets. limited number original hypothesis inventors holds, lanes symmetrically distributed over space between one single general, asymmetric distribution, typically, ratchet suitable applications strong distribution. there not but two determine inside As first approach (and largest) width, df,1 df,N. Consequently, expected motions motion. Its existence become evident experiments described 4, named mixed irregular, contrast intermediate angles corresponding 0 tracked speed recording, were quantified tailor-made analysis. expected, transitions types occur basis length scales, stated certainty experimental error due wide Because 4 been specifically designed investigate behaviors, new df,N, via simulations, order allow investigation. Although scales do take all aspects play role movement account, initial guideline Next, performed computationally intensive, include particles. These check validity derived only flow. transition occurs indeed scale, df,1, being lane. scale determining occurrence might even uncorrelated it. We concluded second df,c, simulations. thus obtained rules experimentally correlate observed exhibiting scales. us confident, now identified relevant concluding discuss chose ultimately derive implications corrected key performance indicators ratchets, find obtaining correct requires intensive Specifically compact designs, application, df,c much - may offer time-efficient way estimating df,c. Further, discussed terms polydisperse suspensions, compactness, selectivity, decrease, same time also opens multiple streams step.