Experimental Investigation Of Thermal Properties Research Articles

Experimental Investigation of Thermal Properties of Frozen Tap, Demineralized, and Sea Water

Experimental Investigation of Thermal Properties of Frozen Tap, Demineralized, and Sea Water

Experimental investigation of thermal properties of tool steel and mild steel with heat treatment

The determination of the thermal properties of materials like H13 tool steel and mild steel has received great attention due to their wide applications in industrial as well as in manufacturing sectors. Due to the excellent resistance to softening, AISI H13 tool steel is widely used for higher temperature applications like cutting, forming and shaping the materials. The parameters that relate the interfacial heat transfer and interface temperature are thermal conductivity and thermal contact conductance (TCC) of the materials in contact. Thermal properties are affected by the heat treatment processes which are mainly employed for the formation of tools and dies. Hence in his work, different heat treatment processes have been performed on the selected materials, viz. Tool steel (H13) and Mild steel. These materials have been chosen for their extensive use in making tools, dies and other instruments. Microhardness of the materials has been compared with and without heat treatments. Further, heat transfer studies have been performed in order to evaluate the thermal properties mainly thermal conductivity and thermal contact conductance. Standard ASTM test methods have been employed for the estimation of thermal conductivity and TCC of the specimens. Experiments have been conducted for varying degree of loading and heat flux in order to observe the effect of contact pressure and mean interface temperatures. Effect of heat treatment has been observed on thermal conductivity of mild steel and tool steel and thermal contact conductance of the tool steel-mild steel contacts. Moreover, the results have been presented in normalized form and suitably compared with the existing literatures.

Experimental investigation of thermal properties and moisture buffering performance of composite interior finishing materials under different airflow conditions

The thermal and humidity environment of indoor air affects the health and comfort of building occupants and the durability of building structures. One potential solution for moderating the thermal and humidity environment is provided by functional materials used for interior finishing, if it can passively buffer heat and moisture. Considering that airflow occurs at all times and locations in buildings, this study focused on the moisture buffering performance under different airflow conditions. A gypsum board was used as a hygroscopic material for interior finishing and was mixed with a microencapsulated phase change material (MPCM) to prepare composite hygroscopic MPCMs. The biomass painting material was another functional material for interior finishing and was prepared by blending scallop shell powder and a PCM slurry. Their thermal properties, such as the thermal conductivity and enthalpy, were tested, along with the hygroscopic properties, such as the pore-size distribution, equilibrium moisture content curve, and water vapor permeability. Scanning electron microscopy indicated that the MPCMs adhered well to and were retained on the laminated structure of the gypsum board. The moisture buffering performance of each sample was tested, and the results indicated that the maximum moisture absorption/desorption of each sample increased with the airflow rate. The ideal moisture buffering value (MBVideal) and practical moisture buffering value (MBVpractical) of each sample were determined and compared in different cases. Additionally, a simple linear model for MBVpractical and the airflow rate was established to predict the influence of the airflow rate on MBVpractical.

Experimental investigation of thermal properties and fire behavior of carbon/epoxy laminate and its foam core sandwich composite

According to structural characteristics, composites are classified as laminated structure and sandwich structure. Carbon/epoxy laminate and foam core sandwich composite are the most commonly used laminate and sandwich structure material in the aircraft industry. The flammability of epoxy resins and foam core material is an inherent hazard. Many previous studies focused primarily on their mechanical properties, while the studies on the thermal and fire properties of carbon/epoxy laminate and its foam core sandwich composite have rarely conducted. Therefore, to characterize their thermal and fire properties, a comprehensive experimental investigation and theoretical analysis were carried out in this work using thermogravimetric analysis, cone calorimeter, vertical/horizontal burning tests, limiting oxygen index and scanning electron microscope tests. Several typical characteristic parameters were obtained and analyzed, such as pyrolysis temperature, heat release rate, mass loss, flaming spread rate and limiting oxygen index. These experimental data coupled with theoretical analysis can provide support for fire risk assessment and fire protection design in aircrafts. The carbon/epoxy laminate and foam core sandwich composite are both characterized as the thermally thick materials. The ignition models and mass loss rate models were obtained. Foam core material negatively affects most of the thermal and fire properties of sandwich composite, but the foam core sandwich composite has self-extinguishing behavior during horizontal burning tests, whose LOI is higher than that of carbon/epoxy laminate. Thus, an important conclusion was reached that the ignition position and flame spread direction have critical effect on the fire behavior of foam core material.

Experimental Investigation of Thermal Properties in Glass Fiber Reinforced with Aluminium

A test method of a Guarded heat flow meter are used to measure the thermal conductivity of glass fiber and filled with a aluminum powder epoxy composites using an instrument in accordance with ASTM. This experimental study reveals that the incorporation of aluminum and glass fiber reinforced results in enhancement of thermal conductivity of epoxy resin and thereby improves its heat transfer capability. Fiber metal laminates are good candidates for advanced automobile structural applications due to their high categorical mechanical and thermal properties. The most consequential factor in manufacturing of these laminates is the adhesive bonding between aluminum and FRP layers. Here several glass-fiber reinforced aluminum were laminates with different proportion of bonding adhesion were been manufactured. It was observed that the damage size is more preponderant in laminates with poor interfacial adhesion compared to that of laminates with vigorous adhesion between aluminum and glass layers numerically calculated ones and it is found that the values obtained for various composite models using experimental testing method.

Experimental investigation of thermal properties of cutting fluid using soluble oil-based TiO2 nanofluid

In this study, soluble oil-based titanium dioxide was employed as a drilling fluid to enhance the performance of drilling process in terms of smoothness. The results of drilling process in the presence of titanium dioxide as an additive were compared with the dry condition and once applying pure drilling fluid. Further, forced convective heat transfer coefficient of the soluble oil-based titanium dioxide nanofluid flowing through a horizontal circular tube was also investigated experimentally under constant wall heat flux boundary condition. To this end, soluble oil-based titanium dioxide nanofluids were prepared at the weight concentrations of 0.3, 0.6 and 1%. To have a proper colloidal stability, gum Arabic (GA) was used as a surfactant with 1:1 weight ratio of GA and titanium dioxide. The results showed that the addition of titanium dioxide nanoparticles to the soluble oil decreased significantly the surface roughness of work-piece as well as the drilling temperature as compared to the pure soluble oil and dry condition. Moreover, as the concentration of titanium dioxide increased, the convective heat transfer coefficient increased significantly, and it was further improved by increasing Reynolds number. Note that increasing the concentration of nanoparticle into the base fluid was more effective than that of improving Reynolds number in the range studied herein.

Investigation of thermal properties of mid-infrared AlGaAs/GaAs quantum cascade lasers

We report on detailed experimental investigation of thermal properties of AlGaAs/GaAs quantum cascade lasers (QCLs) emitting at wavelength of 9.4 μm. Different mounting options and device geometries are compared in terms of their influence on the relative increase of the active region temperature. High resolution, spatially resolved thermoreflectance is used for mapping temperature distribution over the facet of pulse operated QCLs. The devices’ thermal resistances are derived from experimental data. We also develop a numerical thermal model of QC lasers, solving heat transport equation in 2D and 3D, which includes anisotropy of thermal conductivity. By combining experimental and numerical results, an insight into thermal management in QCLs is gained. Thermal optimization of the design focuses on improving heat dissipation in the device, which is essential to increase the maximal operation temperature of the devices.