Low thermal conductivity is one of the major disadvantages that limit the practical application of energy storage materials. In this paper, the thermal physical properties and thermal conductivity of the composite phase change materials, in which the pentaerythritol is used as the matrix material and graphene/alumina as the thermal conductive fillers, is respectively investigated with experimental

Innovative drying technologies are frequently introduced to minimize various disadvantages of hot air dryers such as high energy consumption and low quality dried products. The aim of this study was to investigate the influence of ultrasound (40 kHz for 10, 20, and 30 min) and intermittent microwave (360, 600 and 900 W at pulse ratios of 1, 2, 3 and 4) on physical properties of carrot during low temperature

Pulsating heat pipes are a relatively newer generation of heat pipe which are wickless thus more economical and less fabrication-intensive. These devices are made of a capillary sized tube bent in a serpentine form to result in a closed system. In this study a single closed loop pulsating heat pipe made of 2 mm internal diameter copper tubing is experimentally investigated for two different bend radii

This paper presents the experimental-based performance evaluation of three different configurations of desiccant integrated direct/indirect evaporative cooling systems. These configurations include (1) Conventional desiccant cooling system with the direct evaporative cooler on process and regeneration sides (Configuration 1); (2) direct evaporative cooler on the process with indirect evaporative cooler

In this paper, the compound heat transfer of convection and radiation in an internal circulating fluidized bed for low temperature oxidation of pulverized coal was numerically simulated. The numerical prediction about the compound heat transfer characteristics and its relationship of convection and radiation was compared with the experimental measurements of low temperature radiation. The discrete

CNT based nanofluids have great potential in the field of heat transfer due to their higher thermal conductivity compared to other categories of nanofluids. However, their applicability to different flow conditions is unknown. The flow behaviour of MWCNT/water nanofluids was investigated in this study under a variety of conditions, including concentration, temperature, and shear stress (0–35 Pa). Non-Newtonian

A numerical study was carried out to explore the influence of triangular with concave edge shaped (TCES) upstream ramp on the film cooling effectiveness (FCE) and flow characteristics. The main objective of this study is to obtain the performance of the newly proposed upstream ramp on FCE and to establish that it provides better thermal protection by increasing the lateral diffusion of coolant on the

Silica (SiO2) aerogels are widely used in high-temperature insulation materials due to their low thermal conductivity. The hydrophobicity of SiO2 aerogels is considerably important for maintaining high-thermal insulation performance for a long duration. Traditional methods for the hydrophobic modification of SiO2 aerogels involve the modification of organic functional groups present on aerogel surfaces

The absorber plate surface modifications of a solar air heater (SAH) increase the convective heat transfer rate of the inlet air. Forced convection heat transfer of air in a SAH with a staggered arrangement of conical obstacles has been carried out experimentally and numerically at mass flow rates (0.04, 0.08, and 0.1 kg/s) under ambient conditions for the aim of to enhance the thermal efficiency and

This work presents a study on the evaporation of a volatile liquid droplet placed on a substrate and surrounded by air. We consider in this work the case of a pure liquid droplet (water, ethanol and butanol), and the case of a binary mixture droplet (water-ethanol and water-butanol). The aim of this work is to study the effect of the volatility of each component within a pure or binary droplet on the

A Correction to this paper has been published: https://doi.org/10.1007/s00231-021-03064-3

An implementation of a cooling structure using Two-Phase Loop Thermosiphons (TPLTs) to cool the shaft in a motorized spindle was developed and tested. For this purpose, a shaft with a cooling structure based on TPLTs was designed and tested at rotational speeds of 1000–2000 rpm and a heating power of 50–250 W. Subsequently, the temperature field distribution of a motorized spindle with TPLTs cooling

Performance of two kinds of energy storage methods used in the household refrigeration is investigated and analyzed. A Mixture of De-ionized water with Natural graphite (3 wt%) and Paraffin (OM–46) were considered for phase change material (PCM) in the evaporator side and the condenser side respectively. After thorough investigation through experimental verification it is inferred that this set up

Hydrate flow obstacles encountered during the exploitation of deep-water gas fields has received an increased attention. Based on the variations in the wellbore temperature of a deep-water gas well during the initial restarting period, and considering the interrelationship between the hydrate behavior and heat transfer, a prediction model for hydrate flow obstacle was established by comprehensively

The present work focusses on the comparative study of cooling performance of nano encapsulated phase change material (nanoPCM) based heat transfer fluid (PCM nanofluid) and deionized water in a minichannel heat sink (MCHS) with a hydraulic diameter of 2.6 mm. Polystyrene encapsulated n-Docosane was synthesised by mini emulsion polymerisation. The melting point and latent heat of nanoPCM was found to

A fully coupled model is proposed to investigate the influence of flow on electrochemical mass transfer at the interface between the electrolyte and an electrically conductive droplet. The electric current flows through the droplet, and consequently the droplet acts as both anode and cathode. Computations of flow, concentration of reactant, and electric current density fields were carried out. Various

During cooling, the array jet impact can achieve a rapid and uniform cooling of the high-temperature plate. Previous research results mostly focused on single-jet cooling of thin plates, but the complex flow and heat transfer characteristics between multiple jets could not be obtained. To clarify the heat transfer mechanisms and cooling speed fields characteristics in different flow regions, double

Anode influence on the electroplating system was investigated when natural convection heat transfer in a packed bed is simulated by mass transfer based on the analogy. The cathode to anode area ratio (Ac/Aa) was varied from 1 to 50. For three different anode positions of top and bottom of test section and corner of acryl tank, the distance of anode to cathode bed was varied: 0.01, 0.03, 0.07 m in all

In order to design the vertical falling film evaporators applied in the sewage source heat pump systems, a numerical study employing the VOF (Volume of Fluid) method has been carried out to determine the thickness and the wave behavior of falling liquid film outside a vertical tube. The effects of the annular gap, tube diameter, tube length, spray density, viscosity and surface tension are discussed

Particulate fouling on structured surfaces is typically quantified using the integral thermal or mass-based fouling resistance. The observed geometries may be structures that can improve the heat transfer in heat exchangers (e.g., dimples), cavities in components, or more complex geometries. However, due to limited accessibility or the requirement for a locally resolved measurement, the existing quantification

Numerical simulations were conducted to study the flow and heat transfer characteristics of the dimpled channel with a protrusion. The protrusion was located upstream of the dimple to enhance the flow mixing inside the dimpled channel. The height of the protrusion, h, and the diameter of the protrusion, d, are the variables considered in the present study. The ratio of the height to the diameter of

In this study, tri-ethylene glycol (TEG) based nanofluids of carbon nanotubes (CNT), silica (SiO2) and aluminum oxide (Al2O3) in different weight percents of 0.01 and 0.05 wt% were employed to improve the properties of TEG for water vapor absorption in a hollow fiber membrane contactor (HFMC). To do so, the impact of various operational parameters including nanofluid type, nanoparticles (NPs) concentration

It is well known that the replacement of a round tubes to an oval tube in a fin-and-tube heat exchanger reduces an air-side pressure drop as well as a low performance region behind the tube, and improves the thermal performance of the heat exchanger. However, experimental evidences are lacking, especially for generic heat exchangers. In this study, three generic samples with oval tubes were obtained

Microchannel heat sink is widely utilized as one of the effective heat dissipation methods with lower heat transfer temperature difference. In this paper, visual experiment study has been conducted to focus on the inner relationship between heat transfer/flow properties in macroscopic aspect with bubble dynamic characteristics in microcosmic aspect. Results show that along with the increases of Re

Experimental and Numerical Studies on saturated pool boiling have been carried out over a nichrome wire submerged in both distilled water and silica–water based nanofluids. The concentrations of the silica nanoparticles are varied from 0.01 vol.% to 0.05 vol.% in step size of 0.01. Numerical simulation has been carried out by using Mixture Multiphase Approach. Moreover, heat flux values by applying

This article aims to enhance the efficiency of Diffusion Absorption Refrigeration (DAR) systems which operate at low efficiency. This study experimentally investigates the effect of passive heat transfer enhancement by using various nanofluids as working fluids including ammonia/water couple with different rates of magnesium oxide aluminate spinel (MgOAl2O3) particles. The tests have been carried at

In this work, a new heat dissipation method based on ultra-thin flattened heat pipe (UTHP) is developed for cooling watch-phones. The UTHP with a 0.4 mm thickness was designed to be a three-dimensional shape according to the watchcase shape. The UTHP cooling module (HPM) was soldered by three copper plates and a UTHP. The heat dissipation performance of the copper sheet cooling module (CSM) with the

A Correction to this paper has been published: https://doi.org/10.1007/s00231-021-03048-3

The performance, emission, and combustion characteristics of kapok methyl ester biodiesel in the base engine were analyzed. The kapok methyl ester oil is heated up to 110 °C employing a preheating method to reduce the fuel’s viscosity and density. The preheated oil is blended with the base fuel (i.e., diesel) to make various fuel blends. Many research findings have shown that the B20 (i.e., 20% biodiesel

Natural convection heat transfer within concentric annular pipes has many engineering applications such as in heat exchangers, electronic devices, the nuclear energy sector, aerospace and pipeline systems. Therefore, this investigative research includes three parts, with the first containing numerical simulation to study the natural convection heat transfer in a concentric annular horizontal pipe for

Present paper reports and discusses experimental results related to thermal and flow characteristics of asymmetrical designed flat plate closed loop pulsating heat pipe charged with miscible and immiscible binary fluids. Extensive experimental range is provided for a comprehensive analysis; which covers different binary mixing ratios (H:P, M:H and P:M = 1:1, 1:4 and 4:1) and inclination angles (0°

The condensed working fluid inside a heat pipe is pumped from the condenser to the evaporator section to complete the operating cycle by using the capillary force generated inside the wick structure. Since the miniature heat pipes have smaller vapor cross-sectional area, the fiber wick structure is suitable for this application. The fiber wick structure can be designed to provide an excellent flow

The present article experimentally explored heat transfer through a horizontal metal foam tube with a constant wall heat flux during the subcooled flow boiling of water, Al2O3/H2O, and CuO/H2O nanofluids. To investigate the effect of using metallic foam on the subcooled flow boiling heat transfer, the results have been compared with a simple tube. Besides, The impacts of significant parameters, including

The soil temperature distribution characteristics were experimentally studied, during heat storage and release processes in the fine-grained sand with different moisture content. Results showed that, the soil temperature distributions in the process of soil heat storage and release are almost symmetric under the same excess temperature. The excess temperature is the main factor affecting the soil temperature

The present investigation emphases on rotation effects on internal cooling of gas turbine blades both numerically and experimentally. The primary motivation behind this work is to investigate the possibility of heat transfer enhancement by dean vortices generated by Coriolis force and U-bend with developing turbulent in the view point of the field synergy principle and secondary flow intensity analysis

A great number of studies have been conducted pressure drop for packed bed and curved channel. However, pressure drop in the spiral packed beds has not been investigated. In this study, pressure drop in spiral packed beds which are made of two different channel widths (a = 10 mm and a = 15 mm) and three different ball diameters (d = 2.00, 2.38 and 3.17 mm) was investigated experimentally. Experiments

In the present work, conical frustums (d/D = 0.3) are used as turbulators to form an insert of a heat exchanger tube. Both the perforated and imperforated conical inserts in a diverging arrangement (DR arrangement) are experimentally studied. The effects of the parameters like pitch ratio (p/D), the number of perforated holes (N), and relative location of perforations (x/L) on thermal and fluid characteristics

Fouling phenomena, generally related to heavy crude oils and bituminous petroleum fractions, nevertheless affects significantly the preheat train (PHT) of the light Algerian crude oil. In this study, a two dimensional model was developed using the computational fluid dynamic (CFD) method in order to investigate fouling behavior in the PHT of Algiers refinery. A fouling model was proposed specifically

Salted chickpea (Cicer arietinum L.) is increasingly used in snack production and in home cooking by soaking in brines. Order to achieve better quality and higher nutrient content, it is important to model and understand the mass transfer processes during this operation. In this work, brine salting of chickpea was studied at 1, 5 and 20% salt concentrations, at temperatures of 25, 50, 75 and 100 °C

This study aims to examine and optimize the solvent extraction process of two different liquid-liquid systems, including toluene–acetone-water and n-butylacetate–acetone-water, in a perforated rotating disc contactor (PRDC) pilot plant according to response surface methodology (RSM). The interaction effects of four influential parameters of dispersed phase velocity, and continuous phase velocity, rotor

The thermal conductivity of soil is a fundamental physical property related to heat conduction and also one of the widely applied parameters in geotechnical engineering. Thermal needle tests were performed to measure the thermal conductivity of transparent sand. The thermal conductivity of three particle sizes of transparent sand was measured at different porosities and temperatures. The result shows

Temperature and pressure ratios in gas turbines have grown over time to increase the performance and efficiency of the engine. This, in turn, has required improvements to the effectiveness of the secondary air system to enhance the cooling performance of critical components. Analysis of pressure losses in the secondary systems of aero gas turbines has identified a significant contribution in the bled

Recently, the quality of food solar dried has been associated to solar irradiance, irradiation and UV-light. Different materials used as covering materials in direct solar dryers had different optical properties, thus, different quality should be expected in solar food drying. The objective of this study was to compare two direct solar dryers builder with different covering materials: Direct Solar

This paper reported numerical simulation investigations on heat transfer performance of ZrO2-water and Cu-water nanofluids in the tube with concentric double twisted element(CDTE)(Re = 6000-12000). Furthermore, experiments verified that the two-phase flow model method was more suitable for the numerical simulation of nanofluids in the tube with CDTE. The Nusselt numbers with CDTE and nanofluids obviously

The present work introduces an experimental analysis of an array of 12 elements including two heat sources and the rest are dummy elements. The effect of the second heat source position on the heat transfer coefficient (HTC) of both heat source elements within the Reynolds number range of 4108 ≤ ReL ≤ 17,115 is studied. Moreover, 3D (CFD) numerical model is introduced and its predictions are compared

Open sun Crops drying is common in India even though a considerable time and dust accumulated. This is a serious issue. Workman ship and time reduction is needed to increase the productivity. Introduction of Green house solar dryer should be a right choice as against the conventional drying. The novel research focuses for retaining the nutritional values at higher level, very clean and with very less

The objective of this study is to re-examine the classical parallel and classical series models of the effective thermal conductivity of porous media and review the underlying assumptions used to develop these asymptotic models. The Langmuir shape factor concept is introduced to gain insight into these classical models and add extra degrees of freedom to formulate semi-empirical correlations for the

An existing laboratory scale solar energy accumulator based on phase change materials was adapted to study experimental and analytically its thermoelectric capabilities. Electric power generation levels were assessed to energize low powered systems. Variables of the study were the circulating air velocity at two levels and the cooling convection mechanism on the cold face of the thermoelectric modules

The thermal performance of a double tube two-phase closed thermosyphon (DTTPCT) using alumina nanofluid as working fluid in startup, steady state and shut down modes has been experimentally and theoretically evaluated. Gamma-Alumina (γ-Al2O3) nanoparticles with size of 40 nm were well dispersed, prepared and stabilized in distilled water base fluid at different particle concentrations.The axial wall

The accidental spilling of cryogenic liquid leads to formation of a spreading pool, which may result in pool fires, BLEVE(boiled liquid evaporate vapor explosion) or vapor cloud fire, such as liquefied natural gas, is flammable. The key aspect of evaluating the consequence of such a disaster is to predict vaporization rate of the spreading cryogenic liquid pool. In this study, an empirical function

With the continuing development in the electric industry, highly efficient heat dissipation is of great significance due to the shrinkage of electric elements and increase in energy input. Working fluid, acting as a heat transfer medium, plays a core role in the thermal management. While, traditionally used working fluids suffer from either low thermal conductivity or relatively narrow liquid range

A modified so-called standard apparatus for heat transfer measurements in highly viscous binary fluids has been developed. It covers a viscosity range from 0.2 mPa∙s up to 1000 Pa∙s and is designed for measurements over a temperature range from 273 to 423 K. Concept and setup of the apparatus are described in detail, and uncertainties of the different elements of the measurement chain are discussed

The quantity of energy consumers in the country is extensive in the current quick-moving situation; the whole car industry puts a significant part in energy utilization. Biofuels have lured consideration among other alternative fuels as indicated by their natural element and synthetic creation.In this test, the aluminum nanoparticles are prepared by three various proportions (50, 100 and 150 ppm) being

The thermal enhancement and pressure drop in a circular tube with radially-arrayed winglet vortex generator (VG) mounted inside at different orientations were experimentally studied. A series of four winglet rings containing VGs were on the inner surface of the tube at different sections. The effects of winglet attack angles β (0–45°), pitch ratios PR (1.6–4.8), porosity ratio γ (0–20%), winglet length

A scale analysis has been performed to investigate the film boiling heat transfer associated with cooling of a horizontal flat plate through water jet impinging. The forced convection film boiling of water is treated by classifying a wide spectrum of subcooling regime by two extreme situations of low and high subcooling dominated by mass evaporation and sensible heating respectively. A simple expression

The effects of bubble size, solids particle (impurities) and the respective physical mechanisms on gas–liquid columns have received little attention. Therefore, the objective of this work is to study the effect of solid concentration and the ratio of the bubble diameter to the solid diameter on the mass transfer characteristics. Experiments were conducted in a three phase electroflotation column for

We studied the heat transfer of finned heat exchanger configurations with a novel design. These novel fin designs use integrated pins to enhance the heat conduction from the fin base to the fin tip as well as the air-side heat transfer on the fin surface. Oval tubes with conventional circular plain fins (CPF) as well as novel circular integrated pin fins (CIPF) and serrated integrated pin fins (SIPF)

Growing technological developments to improve the thermal efficiency of heat pipes resulted in many innovative techniques. The use of nanofluids with superior thermophysical properties compared to conventional fluids is one such technique. However, the service life of nanofluid driven heat pipes is affected by agglomeration and stability issues, demanding an alternate solution. Boiling heat transfer

Enhanced heat transfer through minichannel heat sink is beneficial for engineering uses such as air conditioning, cooling system, and heat retrieval processes. In the current study, the heat transfer and friction factor were experimentally measured in a rectangular minichannel heat sink with coiled wire inserts. These coiled wires exhibited two wire diameters (0.4, 0.6 mm) and three pitches (1.2, 2

During the construction of clay core rockfill dam in cold regions in winter, the heat transfer characteristics of gravelly soil are important to the anti-freezing control of the core. Laboratory experiment and field test data showed that the frost depth of gravelly soil in unconsolidated state was deeper than that in compacted state at the early period of soil freezing. With the increase of the freezing