Anuj Kumar Shukla

Bio: Anuj Kumar Shukla is an academic researcher from Indian Institute of Technology Delhi. The author has contributed to research in topics: Nusselt number & Turbulence. The author has an hindex of 7, co-authored 14 publications receiving 140 citations.

Flow and thermal characteristics of jet impingement: comprehensive review

Abstract: A comprehensive review on jet impingement heat transfer is presented to consider the state-of the art in this field. Among all the single-phase heat transfer arrangements possible, it has the maximum heat transfer rate. A number of arrangements are possible to represent a practical or physical situation, such as, jet impingement on a solid flat surface or surface fitted with different kinds of turbulent promoters, inclined plane surface and cylindrical convex/concave surface, etc. A significant number of papers dealing with experimental and computational studies on different physical and computational aspects of jet impinging flows are reviewed. Several parameters were found to influence the characteristics, such as, flow confinement, nozzle shape, jet to plate spacing and Reynolds number. An extremely small number of studies dealing with application based jet impingement heat transfer configurations (e.g., ribs fitted impingement plate, moving impingement plate, etc) experimentally and numerically have been reported in the literature. Various computational approaches, such as, RANS, LES, DNS and hybrid models, that are used to study the jet impingement heat transfer, with their complexities and boundary conditions, have been reviewed. It was observed that majority of RANS based turbulence models did not predict impinging flows accurately and its complexities except a few. Many authors have reported that LES is capable of predicting the flow field and heat transfer data within the accepted accuracy limits. DNS can be applied to simple geometry with low Reynolds number. Recently some authors have employed hybrid models, such as, PANS, DES, etc., and concluded that these models provide reasonably accurate results and were found to be computationally less expensive than LES and DNS.

NiFe2O4/Poly(1,6-heptadiyne) Nanocomposite Energy-Storage Device for Electrical and Electronic Applications.

Abstract: In present study, we have synthesized intrinsically conductive poly(1,6-heptadiynes) via cyclopolymerization technique, and further it is composited with the NiFe2O4 to fabricate pellet for electrical and electronic applications. The synthesized polymer I–V characteristics were obtained by two-probe measurement technique. The results suggest that the high current density of the synthesized polymer was in the range of 1.2 × 10–5–3.1 × 10–5 S/cm, which attributes to the potentially induced hoping charge-carrier mechanism within the conjugated poly(1,6-heptadiynes). NiFe2O4 and NiFe2O4/poly(1,6-heptadiynes) composite pellets were fabricated by utilizing hydraulic pelletizer. The sample’s electrical measurements were performed via broad-band dielectric impedance spectroscopy, wherein the composite permittivity was about e = 45 (100 Hz to 10 kHz), which attributes to the NiFe2O4 and poly(1,6-heptadiynes) phases; further, this describes the capacitance, which improved from 0.3 to 0.1 pf at 1 kHz. Also, these re...

Dielectric and conductivity investigation of polycarbonate-copper phthalocyanine electrospun nonwoven fibres for electrical and electronic application

Abstract: Nonwoven fabric composite formulating polycarbonate (PC) and CuPc was fabricated using electrospun (CuPc: 0 to 10 wt%). Spatial presence of CuPc in composites was ascertained by virtue of F...

OpenFOAM based LES of slot jet impingement heat transfer at low nozzle to plate spacing using four SGS models

Abstract: The objective of the present investigation is to assess the effectiveness of large eddy simulation (LES) in turbulent slot jet impingement heat transfer at low nozzle to plate spacing Four different sub-grid stress (SGS) models, namely, Smagorinsky, WALE (wall adapting local eddy-viscosity), k-equation and dynamic k-equation, were considered for Reynolds number of 20,000 Computations were performed using OpenFOAM, an open source finite-volume based CFD code Time and span-wise averaged mean streamwise velocity and root mean square (rms) velocity fluctuations in the stagnation and wall jet regions are presented Nusselt number distributions on the impingement wall are also presented The computed LES results are compared with the reported experimental data A secondary peak in the Nusselt number was observed using the four SGS models as in the experimental data LES of slot jet impingement heat transfer using four SGS models, including WALE, has been investigated for the first time in the present paper It is observed that the WALE and dynamic k-equation SGS models perform well in complex flow regions of turbulent slot jet impingement heat transfer

Origin of dynamical properties in PMMA-C$_{60}$ nanocomposites

Abstract: Poly(methyl methacrylate) (PMMA)−C60 nanocomposites, with compositions in the range 0 ≤ φC60wt ≤ 0.05, are shown to exhibit systematic increases in dynamic shear moduli, in glass transition temperature (Tg), and in the longest relaxation time of the polymer (τR) with increasing fullerene concentration. We show that while the φC60wt dependence of the plateau modulus can be reconciled with a conventional “filler” effect, the systematic increases in Tg and in τR are associated with specific interactions between the C60 and the polymer segments. In the melt, these segment−C60 interactions are proposed to reduce polymer segmental mobility in the vicinity of the particle surface and ultimately suppress polymer dynamics, as measured mechanically, in a manner consistent with an increase in the polymer segmental friction coefficient.