Nusselt Number and Convection Heat Transfer Coefficient for a Coaxial Heat Exchanger Using Al2O3-Water pH=5 Nanofluid

Răzvan-Silviu Luciu ; Theodor Mateescu ; Victoria Cotorobai ; Thierry Mare

experimental; nanofluid; Nusselt number.

Recently, a new class of fluid made up of metal nano-particles in suspension in a liquid, called nanofluid, appeared. Some numerical studies have shown that these new fluids have a higher heat transfer performance, compared with the conventional liquids. In the present study, we have attempted to study, by experimentation, the thermal performances of a particular nanofluid composed of aluminum oxide ($gamma$ce{Al2O3}) particles dispersed in water for various concentrations ranging ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 71-80 (2009)

en

High Performance Concrete

Traian Oneţ

high strength concrete; high performance concrete; self-compacting concrete; rigid pavement of roads.

The paper presents the last studies and researches accomplished in Cluj-Napoca related to high performance concrete, high strength concrete and self compacting concrete. The purpose of this paper is to raid upon the advantages and inconveniences when a particular concrete type is used. Two concrete recipes are presented, namely for the concrete used in rigid pavement for roads and another one for self-compacting concrete.

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 9-12 (2009)

en

Étude concernant l’effet de mise à la terre dans le système de protection liaison au neutre

Jan Ignat ; Nelu-Cristian Cherecheş ; Cătălin Popovici

canal vertical; simulation numérique; convection libre; régime d’écoulement.

La sécurité des consommateurs de l’énergie électrique fait partie des principales demandes de la Loi 10/95, concernant la qualité dans les bâtiments. Le risque d’un choc électrique doit être diminué en adoptant un système de protection basé sur un moyen de base et un ou plusieurs complémentaires. Dans cet article, on étudie l’effet de mise à la terre, comme moyen complémentaire de celui de base qui adopte la liaison au conducteur du neutre. Cette étude se justifie de plus par ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 13-20 (2009)

fr

Differential Equation of a Visco-Elastic Beam Subjected to Bending

M. Vrabie ; Ionuţ-Ovidiu Toma ; Şt. Jerca

Kelvin-Voight model; Galerkin method; finite differences method.

Generally, building materials exhibit a rheological behaviour as a direct consequence of their fundamental material properties such as elasticity, viscosity and plasticity. Based on the Kelvin--Voight model, governing the behaviour of the visco-elastic materials such as concrete, the present paper proposes the differential equation corresponding to the middle line of a visco-elastic beam subjected to bending. The derived equation is then used in the finite element analysis of ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 21-32 (2009)

en

About Variable Speed Heating and Cooling Pumps

Cătălin Popovici ; Jan Ignat

variable speed pumps; heating; cooling; pump head; pumping cost.

The present work has the purpose of underlying the advantages of variable speed heating and cooling pumps use for the perspective of general and particular pumping costs and efficiency. The study approaches comparisons between constant flow pumps and variable flow pumps in different given situations and comparatively analyses the pumping costs.

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 33-42 (2009)

en

Étude numérique des régimes d’écoulement en convection naturelle dans une façade type double-peau

Nelu-Cristian Cherecheş ; Cătălin Popa ; Monica Cherecheş

canal vertical; simulation numérique; convection libre; régime d’écoulement.

Des simulations sur l’écoulement dans un canal, à l’instar des façades double-peau, ont été menées numériquement afin de déterminer les champs de température et de vitesse sous l’influence de la variation du nombre de Rayleigh modifié qui dépend lui-même des caractéristiques du fluide et du flux de chaleur reçu. Le comportement des couches limites en convection naturelle est analysé au long d’un canal plan vertical dont nous avons une zone chauffée périodiquement à flux imposé. ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 43-52 (2009)

fr

An Incursion on Punching of Reinforced Concrete Flat Slabs

Dan-Vasile Bompa ; Traian Oneţ

punching; flat-slab-column connection; concrete behaviour; code design comparison.

Starting from the early 60s continuous studies have been made regarding punching of concrete flat slabs. The evolution of technology and calculus systems influenced this engineering branch. Nowadays is possible to account in structural analysis all the non-linear behaviour of reinforced and prestressed concrete and to get the most close structural response in comparison with the real behaviour. As a controversy matter, several tests and theories have been developed. Nowadays researchers ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 53-62 (2009)

en

Method for Bubbledeck Concrete Slab with Gaps

Sergiu Călin ; Ciprian Asăvoaie

concrete slab; spherical bubbles; reinforcement; process optimized.

The composite slabs are made of BubbleDeck type slab elements with spherical gaps, poured in place on transversal and longitudinal directions. By introducing the gaps leads to a 30.50% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. BubbleDeck slab elements are plates with ribs on two directions made of reinforced concrete or precast concrete with spherical shaped bubbles. These slab elements have a bottom and an ...

Gheorghe Asachi Technical University of Jassy

2009

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LV (LIX), Fascicle 2, pages 63-70 (2009)

en

Convective Heat Transfer Analysis in Fluid Flow with Turbulence Promoters with Heat Pipes

Andrei Burlacu ; Theodor Mateescu

-

The present paper proposes the analysis and the simulation of the convection heat transfer into the fluid flow with turbulence promoters utilizing heat pipes. The study is based on the necesity of the unconventional energy forms capitalization, increasing of the energy efficiency and leads to the energy consumtion decrease in concordance with the sustainable development concept.

Gheorghe Asachi Technical University of Jassy

2007

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LIII (LVII), Fascicle 1-2, pages 125-132 (2007)

en

Alternative Solution for Consumption Hot Water Recirculation for the Civil Buildings

Theodor Mateescu

-

The sanitary comfort and the effective cost of maintenance in the civil buildings (block of flats) are badly affected by the absence of the consumption hot water recirculation. From the technical point of view, the classical solution imposes the doubling of the transport and distribution pipes on the entire route, between the source and the consumption points. The materialization of the solution requires important financial investment, discouraging most of the time and the postponement ...

Gheorghe Asachi Technical University of Jassy

2007

peer-reviewed article

Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section, Tomme LIII (LVII), Fascicle 1-2, pages 119-124 (2007)

en