Subhashis Patari

 

Research Interests

Fundamental understanding of Capillary rise in paper strips

A liquid can easily flow through the gaps in porous media without using any extra energy due to the inherent capillary action. Darcy first investigated the flow of liquid in porous media experimentally. In 1921 two researchers established the relationship between capillary height and rising time of liquid in porous media famously known as the Lucas-Washburn (L-W) equation. This capillary flow involved the multi-phase flow of liquid and air in micropores of the porous matrix. We have investigated various physical properties of paper, which will affect the liquid flow, such as porosity and permeability. Through experiments and simulations, we have investigated the flow of liquid in paper strips. We used this technique to identify the water content in milk.

 

Paper-based microfluidic device to detect milk adulteration

The consumption of milk is very high because of its precious nutritional value in protein, fat, carbohydrate, vitamin, etc. Being such a vital source of a balanced diet, the demand for milk is huge, and adding adulterants makes this business portable. In such situations of constant supply and increased demand, contamination seems to be one of the accessible escape routes in fulfilling the needs of such a large population. To detect adulterated milk, qualitative and quantitative methods are available. Paper-based microfluidics devices are the best option to perform real-time adulteration detection test.

Dropwise Condensation on metal surfaces

Water vapor condenses on the surface when the surface temperature is lower than the dew point temperature. Condensation is critical for many industrial processes such as thermal power plants, refrigeration systems, water distillation, air conditioning systems, nuclear reactors, etc. There are two modes of condensation, one is Filmwise Condensation (FWC), and the other one is Dropwise Condensation (DWC). DWC provides more heat flux at the same temperature difference compared to FWC.  However, sustaining DWC for a longer duration is difficult to achieve in practice. DWC mainly occurs on lower energy surfaces, but in general, most of the metal surfaces have high surface energy. The nucleation densities for the hydrophilic surfaces are higher than the hydrophobic surfaces. On the pure metal, dropwise condensation (DWC) occurs at low heat flux or the initial phase of the condensation.  In practical engineering applications, the condensate droplets coalesce and form a continuous film, leading to film condensation (FWC). During FWC, the liquid film offers a considerable resistance for heat transfers as well as decreases the new heterogeneous nucleation sites. The objective of this undergraduate project was to perform experiments of dropwise condensation on different surfaces. 

 

Visible Research Output

  1. Patari, S.; Mahapatra, P.S. Liquid wicking in the paper strip: an experimental and numerical study. ACS Omega (Under Review).
  2. Patari, S.; Mahapatra, P.S. Spreading of liquids on porous substrate: numerical and experimental studies. Tenth International Colloids Conference (Abstract accepted).

Awards and Recognition

  1. I was recognized for being selected in 12th position in PMRF in the specialization of mechanical engineering all over India.   
  2. School of Science awarded me as a meritorious student for getting a place in the top 10 in a competitive exam.
  3. Apart from my academic career, I practice yoga, which leads me to get a gold medal in the state-level yoga championship and securing an overall 4th position at the national level.

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