Enhancing thermal conductivity of fluids with nano-particles
01 Jan 1995-Vol. 231, pp 99-105
About: The article was published on 1995-01-01 and is currently open access. It has received 7263 citations till now. The article focuses on the topics: Thermal conductivity & Nanoparticle.
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TL;DR: In this paper, a comprehensive review is carried out to investigate the impact of nanorefrigerant and nanolubricant on energy saving in the refrigeration system, and the results showed that the best energy saving with 21% less energy used was with the use of 0.5% volume ZnO-R152a refrigerant nanol lubricant.
Abstract: Refrigeration system is one of the biggest reason of the expanding pattern of energy consumption, thus, energy saving is one of the best approach to overcome this issue. Nanofluids show extraordinary potential in upgrading the thermodynamic and mechanical performance of the refrigeration system. In the refrigeration system, the effort to improve the efficiency of the system is by introducing nanoparticles in refrigerant (nanorefrigerant) and in lubricant (nanolubricant). In this paper, a comprehensive review is carried out to investigate the impact of nanorefrigerant and nanolubricant on energy saving. The overview consists of properties enhancement of nanorefrigerant and nanolubricant, tribological performance, heat transfer enhancement, performance in heat exchanger, improvement in refrigeration system and pressure drop characteristic. The previous results showed that the best energy saving with 21% less energy used was with the use of 0.5% volume ZnO-R152a refrigerant nanolubricant. Both the suction pressure and discharge pressure were brought down by 10.5% when nanorefrigerant was utilized. The evaporator temperature was lessened by 6% with the utilization of nanorefrigerant. The replacement of R134a with R152a gives a green and clean environment, with zero ozone depleting potential (ODP) and less global warming potential (GWP). The performance of refrigeration system was significantly enhanced.
144 citations
TL;DR: In this paper, forced convection flows of nanofluids consisting of water with TiO2 and Al2O3 nanoparticles in a horizontal tube with constant wall temperature are investigated numerically.
144 citations
TL;DR: In this article, a differentially heated and vertically partially layered porous cavity filled with a nanofluid is studied numerically based on double-domain formulation, and the conservation of mass, momentum, and energy with the entity of nanoparticles in the fluid filling the cavity and that are saturated in the porous layer are modeled and solved numerically using under successive relaxation upwind finite difference scheme.
Abstract: Natural convection heat transfer in a differentially heated and vertically partially layered porous cavity filled with a nanofluid is studied numerically based on double–domain formulation. The left wall, which is adjacent to the porous layer, is isothermally heated, while the right wall is isothermally cooled. The top and bottom walls of the cavity are thermally insulated. Impermeable cavity walls are considered except the interface between the porous layer and the nanofluid layer. The Darcy–Brinkman model is invoked for the porous layer which is saturated with the same nanofluid. Equations govern the conservation of mass, momentum, and energy with the entity of nanoparticles in the fluid filling the cavity and that are saturated in the porous layer are modeled and solved numerically using under successive relaxation upwind finite difference scheme. The contribution of five parameters are studied, these are; nanoparticle volume fraction ϕ (0–0.1), porous layer thickness Xp(0–0.9), Darcy number Da (10−7–1...
144 citations
TL;DR: In this paper, an experimental investigation has been carried out to study the heat transfer and pressure drop characteristics of nanofluid flow inside horizontal helical tube under constant heat flux.
144 citations
TL;DR: In this paper, the authors analyzed the flow of three-dimensional water-based nanofluid over an exponentially stretching sheet, where the transport equations were transformed into nonlinear, coupled similarity equations using 3D exponential type similarity transformations.
Abstract: The aim of the present study is to analyze the flow of three-dimensional water-based nanofluid over an exponentially stretching sheet. The transport equations are transformed into nonlinear, coupled similarity equations using three-dimensional exponential type similarity transformations. These equations are solved numerically to obtain the velocities and temperature in the respective boundary layers. Results are presented to illustrate the effects of various parameters including the temperature exponent, stretching parameter and volume fraction of three different types of nanoparticles, such as copper (Cu), alumina (Al2O3) and titanium dioxide (TiO2) with water as a base fluid.
144 citations