Viscous flow under an elastic sheet

Peng, Gunnar G.; Lister, Joseph

doi:10.1017/jfm.2020.745

Cited by 18 publications

(20 citation statements)

References 24 publications

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“…However, as shown in Figure 6 , when the voltage was 6 V, the highest temperature of the heating resistors was about 300 °C, and this temperature was too low to cause most of the liquid in the chamber to vaporize instantly in a short period, while there was lower ink-droplet overflow from the nozzle. Due to the surface tension and the viscous force between the inks [ 31 ], the ink droplets eventually accumulated around the nozzle. When the time of inkjet printing was increased, the accumulation of ink liquid around the nozzle also increased, which prevented the subsequent ink droplets from being ejected from the nozzle properly, and eventually caused the nozzle blockage.…”

Section: Resultsmentioning

confidence: 99%

Design of Chopsticks-Shaped Heating Resistors for a Thermal Inkjet: Based on TaN Film

Peng

Sun³

et al. 2022

Micromachines

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Efficient printing frequency is critical for thermal bubble inkjet printing, while the difficulty lies in the structural design and material selection of the heating resistors. In this paper, a TaN film was used as the main material of the heating resistors, and two TaN films were placed in parallel to form the chopsticks-shaped structure. The heating time was divided into two sections, in which 0–0.1 μs was the preheating and 1.2–1.8 μs was the primary heating. At 1.8 μs, the maximum temperature of the Si3N4 film could reach about 1100 °C. At the same time, the SiO2 film was added between the TaN film and Si3N4 film as a buffer layer, which effectively avoided the rupture of the Si3N4 film due to excessive thermal stress. Inside the inkjet print head, the maximum temperature of the chamber reached about 680 °C at 2.5 μs. Due to the high power of the heating resistors, the working time was greatly reduced and the frequency of the inkjet printing was effectively increased. At the interface between the back of the chip and the cartridge, the SiO2 film was used to connect to ensure a timely ink supply. Under the condition of 12 V at 40 kHz, the inkjet chip could print efficiently with 10 nozzles at the same time. The inkjet chip proposed in this paper is not limited to only office printing, but also provides a new reference for 3D printing, cell printing, and vegetable and fruit printing.

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Section: Resultsmentioning

confidence: 99%

Design of Chopsticks-Shaped Heating Resistors for a Thermal Inkjet: Based on TaN Film

Peng

Sun³

et al. 2022

Micromachines

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“…When two elastic sheets are separated by a lubricating layer of fluid, the flow of the fluid can cause the sheets to peel. This situation is common in many applications in nature and industry, for example exfoliation of graphene sheets [60], hydraulic fracturing [61], and cell sorting [62]. This study investigates how non-Newtonian liquids can alter peeling behavior of the sheets.…”

Section: Discussionmentioning

confidence: 99%

Peeling of linearly elastic sheets using complex fluids at low Reynolds numbers

Venkatesh¹,

Anand²,

Narsimhan³

2022

Preprint

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We investigate the transient, fluid structure interaction (FSI) of a non-Newtonian fluid peeling two Hookean sheets at low Reynolds numbers (Re 1). Two different non-Newtonian fluids are considered -a simplified Phan-Thien-Tanner (sPTT) model, and an inelastic fluid with shear thinning viscosity (generalized Newtonian fluid). In the limit of small gap between the sheets, we invoke a lubrication approximation and numerically solve for the gap height between the two sheets during the start-up of a pressurecontrolled flow. What we observe is that for an impulse pressure applied to the sheet inlet, the peeling front moves diffusively (x f ∼ t 1/2 ) toward the end of the sheet when the fluid is Newtonian. However, when one examines a complex fluid with shear thinning, the propagation front moves sub-diffusively in time (x f ∼ t α , α < 0.5), but ultimately reaches the end faster due to an order of magnitude larger prefactor for the propagation speed. We provide scaling analyses and similarity solutions to delineate several regimes of peeling based on the sheet elasticity, flow Weissenberg number (for sPTT fluid), and shear thinning exponent (for generalized Newtonian fluid). To conclude, this study aims to afford to the experimentalist a system of knowledge to apriori delineate the peeling characteristics of a certain class of complex fluids.

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“…When the flow rate is slow, the inner friction generated on the wall of the pipe has the guiding function of flow; when the flow rate is too fast, the force on the wall of the pipe acts to obstruct the flow. The principle of viscous force [24,25] of fluid is as follows:…”

Section: Simulationmentioning

confidence: 99%

Design of H-Shape Chamber in Thermal Bubble Printer

Peng

Sun³

et al. 2022

Micromachines

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The utilization rate of ink liquid in the chamber is critical for the thermal bubble inkjet head. The difficult problem faced by the thermal bubble inkjet printing is how to maximize the use of ink in the chamber and increase the printing frequency. In this paper, by adding a flow restrictor and two narrow channels into the chamber, the H-shape flow-limiting structure is formed. At 1.8 μs, the speed of bubble expansion reaches the maximum, and after passing through the narrow channel, the maximum reverse flow rate of ink decreased by 25%. When the vapor bubble disappeared, the ink fills the nozzle slowly. At 20 μs, after passing through the narrow channel, the maximum flow rate of the ink increases by 39%. The inkjet printing frequency is 40 kHz, and the volume of the ink droplet is about 13.1 pL. The structure improves the frequency of thermal bubble inkjet printing and can maximize the use of liquid in the chamber, providing a reference for cell printing, 3D printing, bioprinting, and other fields.

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Viscous flow under an elastic sheet

Abstract: Abstract

Cited by 18 publications

References 24 publications

Design of Chopsticks-Shaped Heating Resistors for a Thermal Inkjet: Based on TaN Film

Design of Chopsticks-Shaped Heating Resistors for a Thermal Inkjet: Based on TaN Film

Peeling of linearly elastic sheets using complex fluids at low Reynolds numbers

Design of H-Shape Chamber in Thermal Bubble Printer

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