ABSTRACT Effects of the curved winglet vortex generator inserts (CWVGs) on the forced convection heat transfer, friction factor, and performance evaluation criteria (PEC) interior flow were experimentally examined in this work. The CWVGs manufactured in CNC from aluminum 6061 material were used as the expanded finned surface with different attack angles (α) of 0°, 30°, and 60°. In the study, air was

ABSTRACT Growth in computational capacity combined with a decrease in the size of digital devices has led to increasing demand for more active and efficient cooling of electronics. In this study, an experimental investigation into two different sizes of central orifice Synthetic Jet Actuators (SJAs) is conducted to evaluate their heat transfer as well as noise generation characteristics. Two SJAs (40

ABSTRACT This article reports the heat transfer data obtained from experimenting a novel functionalized nanodiamond (fND) colloid. In this functionalization technique, the nanodiamonds are coupled with molecules of the host fluid via carboxylic bonds, leading to a de-aggregated and fully stable nanodiamond colloid. The colloid flows through a conduction cold plate where the system cools the electronic

ABSTRACT This paper presents a thermal study of a double-layer encapsulation for an interventional medical device, which operates temporarily inside the human esophagus for cardiac imaging. The surface temperature of test samples, representing the device, was assessed by experiments and numerical simulations. The test samples consisted of a heat source, a heat sink and a double-layer encapsulation

ABSTRACT The present paper reports the experimental investigation of nucleate pool boiling heat transfer above heating surface with the creation of new geometric micro-cavities. Cylindrical, cubic, and pentagonal micro-cavities created on heating surface were studied. Micro-cavity surfaces were fabricated using a fiber laser machine. The heat transfer coefficient (HTC) of the heating surfaces were

ABSTRACT This paper quantifies experimentally the effect of ventilation in diesel pool fire (d = 0.6 m) in a cubical compartment of 64 m3 with ventilation opening factor in range of 0.088–2.828 m5/2. The work is addressed to fire safety in nuclear power plant in which ventilated enclosure are frequently used for chemical processing of flammable fuels. In present work, fuel mass loss rate, global CO

ABSTRACT While storing cryogens at atmospheric pressure, the key parameters governing the ullage space temperature profile are the heat leak rate, the rate of evaporation of liquid and release of vapor to maintain an isobaric state, and the initial fill-level. An analytical model, based on the basic thermodynamic laws, is proposed. The model is capable of predicting the spatial and temporal variations

ABSTRACT Flow distortions from upstream combustors generate various and significant changes to the patterns of endwall heat transfer for an aircraft engine. In this study, to model engine-representative oncoming flows into the high-pressure turbine, turbulence and swirl generators are carefully designed at the inlet of a linear turbine cascade. Detailed heat transfer characteristics over the endwall

ABSTRACT Due to external thermal and mechanical stress on proteinaceous fouling layer, a progressive material change, the so-called aging, occurs, which influences both the thermal and mechanical properties. This paper presents a systematic classification of morphological, thermal, and mechanical aging phenomena. The thermal aging of proteinaceous deposits is discussed based on the thermal characterization

ABSTRACT In this study, with an aim to develop a proper effectiveness-NTU relationship of an enthalpy exchanger having a diagonal flow configuration, heat and moisture transfer experiments were conducted. Test samples having a range of diagonal angles were tested, and the effectiveness ratios between the diagonal flow and the cross-flow configuration were obtained as a function of the diagonal angle

(2021). Enhancement in pool boiling heat transfer of ethanol and nanofluid on novel supersonic nanoblown nanofiber textured surface. Experimental Heat Transfer. Ahead of Print.

ABSTRACT In this study, the effects of a commercial coating and its combination with aluminum and copper microparticles were investigated on condensation heat transfer. Thus, the impacts of different coating thicknesses and different weight percentages of microparticles in coatings on the heat transfer coefficient, heat flux, contact angle, and contact angle hysteresis were investigated. The heat transfer

ABSTRACT This study focuses on improving heat transfer from the surface of heated tubes to airflow in the channel. Perforated concave delta winglet vortex generators, which have not been used in previous studies, were implemented in this study to increase the heat transfer rate. In this experimental study, the comparison of perforated concave delta winglet and perforated delta winglet was investigated

ABSTRACT The analysis and evaluation of transient heat transfer are essential to predict stability and safety of helium gas cooling fusion blanket due to plasma disruption. In this study, transient turbulent heat transfer characteristics of helium gas flowing in a narrow tube were experimentally investigated by using a forced convection gas loop. A narrow tube with an inner diameter of 1.8 mm was employed

ABSTRACT In this study, the effects of New Punched Rectangular Vortex Generators (NPRVGs) and Punched Rectangular Vortex Generators (PRVGs) inside a rectangular channel on heat transfer augmentation, Nusselt number, and friction factor were experimentally investigated. Temperature contours and average Nusselt numbers analyzed heat transfer characteristics resulting from the use of vortex generators

ABSTRACT Heat transfer and flow over a cam-shaped tube with various aspect ratios (AR) have been investigated experimentally at two angles of attack, α = 0° and 180°, and 25000 ≤ Re≤ 55000 based on the equivalent diameter. The aspect ratios of the tubes are AR = 1.35, 1.7, 2.07, 2.51, and 3.74. The results show that with the increase in aspect ratio, the drag coefficient decreases. The AR = 3.74 has

ABSTRACT For the development of functional honeycomb plates (FHPs) and efficient resource utilization of straw, based on the measurement of the equivalent thermal conductivity (λE) of paper honeycomb plates (HPs) and FHPs, including straw-core paper honeycomb plates (SHPs), under cold-left and hot-right conditions, the influence mechanism of the system geometry parameters on the convective heat transfer

ABSTRACT The working medium is air in a solar air heater (SAH) and because of its low heat-transfer coefficient, SAH results in poor performance. By placing artificial-roughness over the heat-collector plate, the performance of a SAH can be improved significantly. The improvement in thermal and hydraulic performance by providing multiple-arc-rib roughnesses patterns with the gap is discussed and generalized

ABSTRACT The solar cavity receiver performance is considerably influenced by wind specifications in the parabolic dish system. This paper performs experiments to study the effects of wind direction and speed on the heat losses from a bicylindrical cavity receiver at different inclinations. A range of wind speeds from 0.3 to 5.7 m/s and the three head-on, back-on, and side-on wind directions for the

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

ABSTRACT The aim of this study is to estimate the thermal diffusivity of metallic materials, in particular AISI 304 and AISI 316 stainless steel. To this end, an experimental setup based on the Angstrom’s method is used, where one face of a considerably large sample is subjected to a periodic heat flux and the other face is kept at a constant temperature. A low cost measurement system was developed

ABSTRACT The intensity of delayed fluorescence and kinetics processes of eosin molecules in a hanging drop of water solution with ablative silver nanoparticles and without them during phase change have been investigated in this work. Basing on the fluorescence data the obtained times of the initial stage of water-ice phase transitions were amount to 0.04 s and 0.067 s in solutions with and without

ABSTRACT This paper presents the experimental analysis of partially condensed refrigerant R-32 in an adiabatic straight capillary tube. The capillary test section is tested for variation of the mass flow rate for different inlet conditions. The capillary tube test section is selected for a diameter of 1.12 mm, 1.27 mm, and 1.52 mm, and for length 1000 mm, 1500 mm, and 2000 mm. The capillary inlet pressures

ABSTRACT It is a coupling solution for optimizing the materials with good thermal conductivity and anti-corrosive modified coating of flue-gas condensation heat exchangers. The paper experimentally studied the condensation heat transfer between the wet air and 3-D finned-tube heat exchanger surface in three different ways, i.e. non-coating, Ni-Cu-P organic pure-coating, and Ni-Cu-P chemical organic

ABSTRACT The boiling heat-transfer performances of R1234ze(E)/R152a (0.4/0.6 by mass) flowing inside a horizontal micro-fin tube of 9.52 mm outer diameter were researched by experiment. Under the experimental conditions of mean vapor quality between 0.02 and 0.98 with the mass flux of 50 ~ 100 kg/(m2·s), saturation temperature from 12 to18°C and heat flux from 5 to 20 kW/m2, and the impacts of mass

ABSTRACT The pulse tube refrigerator is a closed cycle mechanical refrigerator with no mobile components working in a low-temperature area. The pulse tube refrigerator provides significant potential and has certain benefits viz., vibration-free, huge reliability, and economical for long span performance. In this paper, the experimental investigations performed on a single-stage Gifford-McMahon type

ABSTRACT The effects of input parameters such as pressure, mass flux, and inlet subcooling on bubble departure diameter, frequencies, and quadrupole magnetic field have been investigated. It was observed that process of changes in diameter and bubble departure frequency was similar with and without magnetic field, and the bubbles proved a regulated growth in the presence of a magnetic field. Compared

ABSTRACT This paper investigates the effect of the combined passive technique on heat transfer enhancement, friction factor, and thermal performance of a double-tube heat exchanger fitted with differently configured turbulators and using Alumina nanofluid. The performance parameters are studied for fixed flow rate (Re = 2500) of water at constant heat flux in the inner tube (hot fluid) and varying

ABSTRACT In this study, the temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. To compare the effects of porous feldspar mortar, two real-size models (control and test model) were constructed. The surface temperature change of the heat storage layer was remotely monitored

ABSTRACT This paper is focused on the effects of different evacuation pressures on thermal performance of vertically placed flat-plate pulsating heat pipe (FP-PHP). Experimental results show that the difference in the amount of non-condensable gas (NCG) caused by evacuation pressures is an important reason for the difference in thermal performance of FP-PHP. The water FP-PHP under evacuation pressure

The thermal performance of a flat-plate solar collector (FPSC) using novel heat transfer fluids of aqueous colloidal dispersions of covalently functionalized multi-walled carbon nanotubes with β-Al...

The present article is focused to improve the thermal performance of solar air heater using Liquid crystal thermography (LCT) approach, an improved type solar air heater comprises of winglet type r...

In this paper, the effect of various zinc oxide aluminate spinel (ZnOAl2O3) and titanium oxide (TiO2) nanoparticle concentrations on the thermal performance of the Diffusion Absorption Refrigeratio...

We report the development of transparent high-thermal-conductivity nanofluids for enhanced flow cooling of solid-state laser crystal rods. The transparent nanofluids were prepared by dispersing cit...

Many troubles appear when vehicles work in the plateau region, and the main reason is that the heat-transfer capability of radiator in the vehicle cooling system reduces under the plateau low air p...

Present experimental study reports the thermal and flow measurement of multiple-orifice synthetic jet involving circular, square, and rectangular orifice shapes. Here, an infrared camera and consta...

Three micro-finned and two smooth multiport tubes having the same tube width and height with the microfin tubes were tested using R-410A. For the smooth multiport tube, the tube with smaller hydrau...

The thermohydraulic effect of microstructuring of the heat transfer surfaces of plate heat exchanger was studied experimentally. The aim of this enhancement strategy is to raise the heat transfer c...

R-134a distribution in an evaporator having two-row/six-pass configuration was experimentally studied with the inlet quality 0.2 and the outlet superheat 5°C. The mass flux was varied from 63 kg/m2...

The assembly step between the vane and blade in a gas turbine exists because of the rotating blade and expansion of the external flow passage. The assembly step has a great impact on the heat trans...

Rates of mass and heat transfer (by analogy) at the surface of a helical coil imbedded in a fixed bed of inert cylindrical packing were measured under upward two-phase (gas-liquid) flow by the elec...

Thermal energy storage system has significant influence on energy conservation. Based on the literature review, it is identified that very few studies have been reported on performance assessment o...

Turbulators have been developed as a capable passive technique for enhancing heat transfer through channels. The shape and arrangement of these geometries are the main factors in their performance....

The condensation heat transfer characteristics of a new environmental refrigerant mixture R1234ze (E)/R152a (mass ratio 40:60, named NCUR01) in a horizontal micro-fin tube with an outer diameter of 9.52 mm were experimentally investigated. Experiments were conducted at saturation temperatures of 30°C, 35°C and 40°C, heat flux ranged from 3 to 8 kW·m−2, mass flux ranged from 25 to 75 kg·m−2·s−1, and

In the context of emission-free electricity generation, the authors developed a novel hydrogen-oxygen combustor, which is based on swirl-stabilized combustion technology and steam dilution. Followi...

Jet impingement on absorber plate with hemispherical protrusion is taken up for heat and friction characteristics analysis, where the protrusions are provided exactly below the jet holes to provide...

Experiments have been conducted on a flat rectangular loop heat pipe with water and methanol at heat loads from 40 to 320 W at three orientations of the heat pipe (0°, 45°, 90°) and two filling rat...

Low-pressure refrigerants such as R245fa allow compact design of IT cooling systems intended for harsh environments. Nucleate boiling of R245fa on an electrically heated flat horizontal surface was...

Steady-state experiments are conducted under the laminar forced convection heat transfer mode for the cooling of seven asymmetric IC chips (heat sources) mounted at different positions on the subst...

An experimental study on the antifouling performance of ultrasonic and/or electronic treatment was carried out in a convective heat transfer process by using a fouling monitor system. An ultrasonic...

This work aims to estimate the experimental heat transfer coefficients of a circular channel using artificial neural network. The experiments are carried out at a forced turbulent flow regime of 10...

The purpose of this experimental study is to measure the drag and heat transfer coefficients of the non-circular tubes including square, elliptic, and cam-shape tubes in a turbulent air cross flow....

An experimental study has been performed to analyze the heat transfer characteristics by impinging a hybrid nanofluid jet on horizontal-heated test surface. The Ag/ZnO nanoparticles are synthesized...

The current paper is focused on the experimental investigation of the turbulent forced convection with circular-hole spring tape (CHST) inserts in a circular tube. The CHST inserts with different h...

ABSTRACT It is hypothesized that the heat transfer in microgravity bubbly flow boiling can be computed through a single-flow simulation that accounts for the acceleration of the liquid as bubbles form since the slip velocity in microgravity is negligible. Measurements within the bubbly flow regime were obtained in a 6 mm ID sapphire tube in microgravity using HFE-7000 at four mass fluxes, six heat

ABSTRACT Effect of upward two-phase gas-liquid flow on the rate of liquid-solid mass transfer in a bubble column equipped with a horizontal tube bundle was studied by measuring the rate of the diffusion-controlled dissolution of copper in an acidified K2Cr2O solution. Variables studied included gas (nitrogen) flow rate, liquid flow rate, and the number of tube arrays. Data were successfully correlated

ABSTRACT Impact of using V-cuts twisted tape insert and phase change material (PCM) dispersed mono or hybrid nanofluid on the hydrothermal characteristics of the double tube heat exchanger is experimentally investigated. Water-based Al2O3 and PCM nanofluids and Al2O3+ PCM hybrid nanofluid with different concentrations are used in inner tube. Influences of various geometric parameters of V-cuts twisted

ABSTRACT In this experimental investigation, the impact of engine load, compression ratio, and percentage blends of biofuel on exergy, energy, and sustainability parameters for the samples of diesel based (10–40% v/v) biodiesel blends were performed on variable compression ratio engine. The brake thermal efficiency, exergy efficiency, engine sustainability, exergy destruction rate, and other exergy

ABSTRACT A version improving the efficiency of the Trombe-type assembly is proposed in this study. It consists in equipping the wall with a series of inclined fins forming open cavities of parallelogram section affecting the aerodynamics of the active cavity. The natural convective flow leads to an increase in natural convective heat transfer and improves the overall performance of the assembly. The

ABSTRACT Critical Heat Flux (CHF) is one of the catastrophic failure modes encountered in two-phase flows in nuclear, chemical, and power industries. Considerable research was carried on CHF in last few decades in horizontal, inclined, and vertically upward flows. Only limited information, mostly at atmospheric pressure conditions and including CHF enhancers like inlet throttling, was available on