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Wang, J. (author), Yan, Xin ping (author), Boersma, B.J. (author), Lu, Ming jian (author), Liu, Xiaohua (author)Printed circuit heat exchangers (PCHE) are designed to improve heat recovery and energy saving in supercritical CO<sub>2</sub> (S-CO<sub>2</sub>) power cycles. In the current study, a modified channel PCHE is proposed based on the regular straight channel and a zigzag channel. The thermal–hydraulic performance of four different types of PCHE...journal article 2023
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Ozmen, Yucel (author), Boersma, B.J. (author)An experimental study was conducted to search the reduction of friction in fully developed turbulent pipe flow using different types of polyacrylamides as friction reducing polymers. Pressure drop measurements determined the friction reduction. Three different polymer types Superfloc A110, Superfloc A130 and Superfloc A150 were used to...journal article 2023
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Çelik, M. (author), Patki, Mrunal (author), Paulussen, Geert (author), de Jong, W. (author), Boersma, B.J. (author)In a conventional continuous annealing line, the energy supplied to steel strip during heating is not recovered while cooling it. Therefore, an alternative heat transfer technology for energy efficient continuous annealing of steel was developed. This technology enables reusing the heat extracted during cooling of the strip in the heating...journal article 2019
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Çelik, M. (author), Paulussen, Geert (author), van Erp, Dennis (author), de Jong, W. (author), Boersma, B.J. (author)Rotating wickless and stationary capillary cylindrical heat pipes are widely used heat transfer devices. Transient behavior of such heat pipes has been investigated numerically with computational fluid dynamics and lumped parameter models. In this paper, the advantages of both methods are combined into a novel engineering model that is low in...journal article 2018
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Çelik, M. (author), Devendran, Kathikeyan (author), Paulussen, Geert (author), Pronk, Pepijn (author), Frinking, Ferry (author), de Jong, W. (author), Boersma, B.J. (author)A new concept for energy efficient annealing of steel strip comprises of multiple rotating heat pipes. Each heat pipe extracts heat from the cooling strip which is reused to increase the temperature of the heating strip. In this context, the heat transfer between the steel strip and the rotating heat pipe is investigated. When the strip is...journal article 2018
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Peeters, J.W.R. (author), Pecnik, Rene (author), Rohde, M. (author), van der Hagen, T.H.J.J. (author), Boersma, B.J. (author)Heat transfer to fluids at supercritical pressure is different from heat transfer at lower pressures due to strong variations of the thermophysical properties with the temperature. We present and analyze results of direct numerical simulations of heat transfer to turbulent CO2 at 8 MPa in an annulus. Periodic streamwise conditions are imposed so...journal article 2017
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Patel, A. (author), Boersma, B.J. (author), Pecnik, Rene (author)Direct numerical simulation of fully developed, internally heated channel flows with isothermal walls is performed using the low-Mach-number approximation of Navier-Stokes equation to investigate the influence of temperature-dependent properties on turbulent scalar statistics. Different constitutive relations for density ρ, viscosity μ, and...journal article 2017
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Sengupta, U. (author), Nemati, H. (author), Boersma, B.J. (author), Pecnik, Rene (author)This work investigates fully developed turbulent flows of carbon-dioxide close to its vapour-liquid critical point in a channel with a hot and a cold wall. Two direct numerical simulations are performed at low Mach numbers, with the trans-critical transition near the channel centre and the cold wall, respectively. An additional simulation...journal article 2017
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Peeters, J.W.R. (author), Pecnik, Rene (author), Rohde, M. (author), van der Hagen, T.H.J.J. (author), Boersma, B.J. (author)Heated or cooled fluids at supercritical pressure show large variations in thermophysical properties, such as the density, dynamic viscosity and molecular Prandtl number, which strongly influence turbulence characteristics. To investigate this, direct numerical simulations were performed of a turbulent flow at supercritical pressure (CO2 at 8...journal article 2016
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Costa, P. (author), Boersma, B.J. (author), Westerweel, J. (author), Breugem, W.P. (author)We present a collision model for particle-particle and particle-wall interactions in interface-resolved simulations of particle-laden flows. Three types of interparticle interactions are taken into account: (1) long- and (2) short-range hydrodynamic interactions, and (3) solid-solid contact. Long-range interactions are incorporated through an...journal article 2015
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Patel, A. (author), Peeters, J.W.R. (author), Boersma, B.J. (author), Pecnik, R. (author)We theoretically and numerically investigate the effect of temperature dependent density and viscosity on turbulence in channel flows. First, a mathematical framework is developed to support the validity of the semi-local scaling as proposed based on heuristic arguments by Huang, Coleman, and Bradshaw [“Compressible turbulent channel flows: DNS...journal article 2015
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Boersma, B.J. (author), Pecnik, R. (author), Nemati, H. (author), Peeters, J.W.R. (author)In this paper we discuss the effect of sharp property variations on the turbulent heat transfer in fluids close the critical point. The governing equations for this flow regime are discussed, a short description of the numerical tools that have been developed to study these flows is given. Finally, some results for supercritical heat transfer in...journal article 2015
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Vuorinen, V. (author), Yu, J. (author), Tirunagari, S. (author), Kaario, O. (author), Larmi, M. (author), Duwig, C. (author), Boersma, B.J. (author)Large-eddy simulations (LES) based on scale-selective implicit filtering are carried out in order to study the effect of nozzle pressure ratios on the characteristics of highly underexpanded jets. Pressure ratios ranging from 4.5 to 8.5 with Reynolds numbers of the order 75?000–140?000 are considered. The studied configuration agrees well with...journal article 2013
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Koschatzky, V. (author), Westerweel, J. (author), Boersma, B.J. (author)The aim of the present study is to compare two different acoustic analogies applied to time-resolved particle image velocimetry (PIV) data for the prediction of the acoustic far-field generated by the flow over a rectangular cavity. We consider the model problem of sound radiating from an open, two-dimensional, shallow cavity with an aspect...journal article 2011
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Boersma, B.J. (author), Breugem, W.P. (author)In this paper we consider a fully developed turbulent flow in a round pipe with a small inner annulus. The diameter of the inner annulus is less than 10% of the diameter of the outer pipe. As a consequence, the surface area of the inner pipe compared to the outer pipe is small. The friction exerted by the wall on the flow is proportional to the...journal article 2010
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Koschatzky, V. (author), Moore, P.D. (author), Westerweel, J. (author), Scarano, F. (author), Boersma, B.J. (author)In this paper, we study the acoustic emissions of the flow over a rectangular cavity. Especially, we investigate the possibility of estimating the acoustic emission by analysis of PIV data. Such a possibility is appealing, since it would allow to directly relate the flow behavior to the aerodynamic noise production. This will help considerably...journal article 2010
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Anand, R.K. (author), Boersma, B.J. (author), Agrawal, A. (author)In this paper, we evaluate several criteria for the detection of turbulent/non-turbulent interface using direct numerical simulation and particle image velocimetry data of an axisymmetric turbulent jet. The possibility of identifying the interface from information available in wholefield velocity data alone is also explored. The present results...journal article 2009
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Slot, H.J. (author), Moore, P. (author), Delfos, R. (author), Boersma, B.J. (author)In this paper we present the experimental results of a detailed investigation of the flow and acoustic properties of a turbulent jet with Mach number 0·75 and Reynolds number 3·5 103. We describe the methods and experimental procedures followed during the measurements, and subsequently present the flow field and acoustic field. The experiment...journal article 2009
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Ooms, G. (author), Boersma, B.J. (author)A study was made of the possible similarity between the development of truncated, inviscid turbulence and the Fermi–Pasta–Ulam (FPU) problem. For the case of a constant time scale, which resembles the FPU problem, a significant increase in the time to achieve equipartition was found when the initial energy was decreased. At first a few modes...journal article 2008
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Mortensen, P.H. (author), Andersson, H.I. (author), Gillissen, J.J.J. (author), Boersma, B.J. (author)The dynamical behavior of tiny elongated particles in a directly simulated turbulent flow field is investigated. The ellipsoidal particles are affected both by inertia and hydrodynamic forces and torques. The time evolution of the particle orientation and translational and rotational motions in a statistically steady channel flow is obtained for...journal article 2008
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