Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 8
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The paper presents the results of a numerical study devoted to the hydraulic properties of a network of parallel triangular microchannels (hydraulic diameter Dh = 110 um). Previous experimental investigations had revealed that pressure drop through the microchannels system dramatically increases for the Reynolds number exceeding value of 10. The disagreement of the experimental findings with the estimations of flow resistance based on the assumption of fully developed flow were suspected to result from the so-called scale effect. Numerical simulations were performed by using the classical system of flow equations (continuity and Navier-Stokes equations) in order to explain the observed discrepancies. The calculations showed a very good agreement with the experimental results proving that there is no scale effect for the microchannels considered, i.e. the relevance of the constitutive flow model applied was confirmed. It was also clearly indicated that the excessive pressure losses in the high Reynolds number range are due to the secondary flows and separations appearing in several regions of the microchannel system.

Go to article

Authors and Affiliations

M. Niklas
M. Favre-Marinet
D. Asendrych
Download PDF Download RIS Download Bibtex

Abstract

Hydraulic and transport properties of periodic open cellular structures (POCS) based on cubic cells were investigated numerically. Different cell and strut dimensions, as well as strut shapes, were examined. Numerical results of heat transfer and flow resistance, as well as modeled morphological parameters were verified experimentally. The most beneficial properties were obtained for the POCS with convex triangular, circular and hexagonal struts.
Go to article

Authors and Affiliations

Marzena Iwaniszyn
1
ORCID: ORCID

  1. Polish Academy of Sciences, Institute of Chemical Engineering, Bałtycka 5, 44-100 Gliwice, Poland
Download PDF Download RIS Download Bibtex

Abstract

Environmental hydraulics is a sub-branch of environmental fluid mechanics that deals with the movement of water and transport processes in both natural water bodies and engineered waterways. Techniques developed to evaluate flow resistance in man-made conduits can be successfully applied to natural waterways.

Go to article

Authors and Affiliations

Jochen Aberle
Download PDF Download RIS Download Bibtex

Abstract

The paper presents the concept of new swirl inserts. An empty two-phase swirl flow atomizer, and three atomizers with inserts were designed, manufactured and tested. The tested atomizers did not differ in terms of their geometric dimensions, with the only variable being the type swirl chamber filling. Flow resistance and spray angle values were analysed for all the evaluated structures. It was shown that the presence of a swirl insert does not significantly increase flow resistance, but instead results in larger spray angles. Taking into account the values of flow resistance and spray angles, the best design solution turned out to be the set of inserts No. 2.
Go to article

Authors and Affiliations

Sylwia Włodarczak
1
Daniel Janecki
2
Bartosz Czajkowski
1
Adam Szmyt
1
Andżelika Krupińska
1
Magdalena Matuszak
1
Marek Ochowiak
1

  1. Department of Chemical Engineering and Equipment, Poznan University of Technology, M. Sklodowska-Curie 5, 60-965 Poznan, Poland
  2. Institute of Environmental Engineering and Biotechnology, University of Opole, 45-032 Opole, Poland
Download PDF Download RIS Download Bibtex

Abstract

In this paper, flow systems which are commonly used in fittings elements such as contractions in ice slurry pipelines, are experimentally investigated. In the study reported in this paper, the consideration was given to the specific features of the ice slurry flow in which the flow behaviour depends mainly on the volume fraction of solid particles. The results of the experimental studies on the flow resistance, presented herein, enabled to determine the loss coefficient during the ice slurry flow through the sudden pipe contraction. The mass fraction of solid particles in the slurry ranged from 5 to 30%. The experimental studies were conducted on a few variants of the most common contractions of copper pipes: 28/22 mm, 28/18 mm, 28/15 mm, 22/18 mm, 22/15 mm and 18/15 mm. The recommended (with respect to minimal flow resistance) range of the Reynolds number (Re about 3000-4000) for the ice slurry flow through sudden contractions was presented in this paper.

Go to article

Authors and Affiliations

Łukasz Mika
Download PDF Download RIS Download Bibtex

Abstract

This paper presents an effect of general dimensions of a reverse flow mini-cyclone with a tangential inlet on its separation efficiency. Several mini-cyclone design modifications are presented and evaluated for use in the air filtration systems of motor vehicles. Local design improvements of three components of a reverse flow mini-cyclone with a tangential inlet D-40 of an air filter fitted in an all-terrain vehicle engine were introduced. An asymmetric curvilinear shape of an outlet port was used instead of a symmetrical shape. An outlet vortex finder inlet port shape was streamlined, and a cylindrical outlet vortex finder of the cyclone was replaced with a conical one. Experimental evaluation of the effects of the design improvements of mini-cyclone on its separation efficiency and performance as well as flow resistance was carried out. Separation efficiency of the cyclone was determined using the mass method as a product of dust mass retained by the mini-cyclone and supplied to the mini-cyclone in a specified time. Separation performance of the cyclone was determined as the largest dust particle dz =dzmax in a specific test cycle in the cyclone outlet air stream. A polydisperse PTC-D test dust used in Poland, a substitute for AC-fine test dust was used. Dust concentration at the mini-cyclone inlet was kept at 1 g/m3. The size and total number of dust particles in the air stream at the outlet of the original mini-cyclone and at the outlet of the improved mini-cyclone was determined using a particle counter.
Go to article

Authors and Affiliations

Tadeusz Dziubak
Download PDF Download RIS Download Bibtex

Abstract

An axial flow tubular heat exchanger has been experimentally investigated to augment the heat transfer rate with a novel swirl flow of air past the heated tubes. The novel design has been based on circular baffle plates provided with trapezoidal air deflectors of various inclination angles. The arrangement of tubes is kept the same throughout the experiment, in accordance with the longitudinal airflow direction. The tubes maintained a constant heat flux condition over the surface. Four deflectors with equal inclination angles were developed on each baffle plate, generating air swirl inside a circular duct carrying the heated tubes that increase air-side turbulence and, consequently, the surface heat transfer rate. The baffle plates were placed equidistant from each other at variable pitch ratios. The Reynolds number was kept in the range of 16000– 28000. The effect of pitch ratios and inclination angles on the thermo-fluid performance of the heat exchanger was studied. The investigations revealed an average improvement of 3.75 times in thermo-fluid performance for an exchanger with a deflector baffle plate with a baffle inclination angle of 50_ and a pitch ratio of 1.4 when compared to other inclination angles and pitch ratios.
Go to article

Authors and Affiliations

Md Atiqur Rahman
1
ORCID: ORCID
Sushil Kumar Dhiman
1

  1. Department of Mechanical Engineering, Birla Institute of Technology, Mesra, Ranchi, India
Download PDF Download RIS Download Bibtex

Abstract

The paper presents research on a novel catalytic carrier, called "streamlined structure". The carrier is a short-channel monolith, whose walls are shaped like an airfoil profile (airplane wing). The intention is heat transfer intensification coupled with moderate flow resistance. Streamlined structures with triangular channel cross-section, 3mm, 6mm and 12 mm long, were designed and manufactured using the SLM (Selective Laser Melting) technique for the experimental verification. The structures were modelled using the CFD (Computational Fluid Dynamics) software to derive flow resistance, flow patterns and heat transfer coefficients. Compared to classic structures, CFD showed intensified heat transfer, combined with acceptable flow resistance increase. CFD proved the lack of an inlet vortex, which in classical structures seriously reduces the intensity of heat transfer. The CFD has been satisfactorily verified by experiments.
Go to article

Authors and Affiliations

Katarzyna Sindera
1
ORCID: ORCID
Mateusz Korpyś
1
ORCID: ORCID
Marzena Iwaniszyn
1
ORCID: ORCID
Anna Gancarczyk
1
ORCID: ORCID
Mikołaj Suwak
1
Andrzej Kołodziej
1 2
ORCID: ORCID

  1. Polish Academy of Sciences, Institute of Chemical Engineering, Bałtycka 5, 44-100 Gliwice, Poland
  2. Opole University of Technology, Faculty of Civil Engineering and Architecture, Katowicka 48, 45-061 Opole, Poland

This page uses 'cookies'. Learn more