Thermophysical Properties Of Nanofluids

The purpose of this experiment was to find the amount and percent of water in a hydrated salt. Hydrated salt contains water molecules chemically bound to it while anhydrous salt is a substance that fire can readily remove the water molecules. Using the gravimetric analysis method, the sample salt was measured, heated, and was measured again after cooled down to room temperature; this procedure allowed the weight of water lost in the salt to be obtained. After two trials, the water in the salt was determined to have an average percent water of -35.04%. The null hypothesis, the heat will not affect the amount of water lost, was rejected ,however, the alternative hypothesis, the heat will allow for there to be water lost, was not supported.

Overall, we were able to discern that calcium chloride would serve as the most effective ionic solid within a hand warmer. Foremost, it served as one of the most effective solids in regards to heat production. The reason being, as seen from our calculations, when one places 10 grams of any of the ionic solids tested in the experiment inside a hand warmer containing an inner pouch of 40 mL of water, calcium chloride has the second greatest expected increase in regards to the heat of the solution. Also, these two compounds have the greatest heat of solution of all the tested ionic compounds. The only ionic solid which trumps calcium chloride in this category, would be lithium chloride. However, due to lithium chloride greater toxicity in comparison to calcium chloride, one will have to deem the latter as our most effective hand warmer. This can be seen as skin must be immediately washed with water when it comes into contact with lithium chloride, such measures are not necessary with the slightly hazardous calcium chloride. Additionally, lithium chloride has the greater personal protection rating in comparison to that of calcium chloride from their respective MSDS sheets, with a rating of E to C. Thus, the former requires a greater degree of protection on the part of the users to prevent harm. Since hand warmers will come into contact with the hands of users, and there is a potential of a leak, calcium chloride is the safest option, as even in the case of a leak, the safety of

As the temperature of water increases, the particles of solid Potassium chloride, KCl, which are absorbing energy from its surrounding, start moving more easily between the solution and its solid state because. According to the second law of thermodynamics, the particles will shift to the more disordered, more highly dispersed solution state. I predict that as the temperature of a KCl and water mixture increases, then the solubility of the KCl will also increase.

Intermolecular forces hold molecules together when they are in solid or liquid state. However, water has the ability to dissociate many salts and ionic compounds. This is called dissolving. When NaCl is added to water, it dissociates into the ions; Na+ and Cl- . The positive sodium ions are surrounded by the slightly negatively charged part of water molecules (i.e. oxygen) in the water molecules and the negative chlorine ions are surrounded by the slightly positively charged part of water molecules (i.e. the hydrogen). The kinetic energy of the sodium chloride molecules increase with temperature. This destabilizes the solid state that it is currently in. This increased motion means that the molecules are less able to hold together and as such they dissolve at faster rates and larger amounts.

Water has a high specific heat capacity compared with other liquids. This means that a large increase in energy results in a comparatively small rise in the temperature of the water. This is because much of the heat absorbed is used to break the hydrogen bonds that hold the molecules together. Water is good at maintaining its temperature at a steady level, irrespective of fluctuations in the temperature of the surrounding environment. This is important because the range of temperatures in which

If you dropped ice cubes into both a sample of water and a sample of methanol, the methanol would cool faster, due to its lower specific heat. A lower specific heat means that for the same heat change, there will be a greater change in temperature.The assumption that can be made from this is that methanol would not make a good coolant, due to its inability to hold it’s temperature.

[4] Engineeringtoolbox.com, 'Thermal Conductivity of some common Materials and Gases', 2015. [Online]. Available: http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html. [Accessed: 20- Jul- 2015].

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This experiment was performed to determine the heat of neutralization between Hydrogen chloride (HCl) and Sodium hydroxide (NaOH). A temperature probe was used to measure the temperature of the reaction when the base (NaOH) was poured into the acid (HCl). The data was collected on logged on LoggerPro.

wool on its own because it has no lid which means heat can be lost

Kandasamy et al. [8] investigated the effects of chemical reaction, heat source and thermal stratification on heat and mass transfer in MHD flow over a vertical stretching surface. Mingchun et al. [9] analyzed the effect of non-thermal equilibrium model of the coupled heat and mass transfer in strong endothermic chemical reaction system of porous media. The problem of combined heat and mass transfer of an electrically conducting fluid in MHD natural convection adjacent to a vertical surface is analyzed by Chen [10] by taking into account the effects of Ohmic heating and viscous dissipation but neglected chemical reaction of the species. Ghaly and Seddeek [11] have investigated the effect of chemical reaction, heat and mass transfer on laminar flow along a semi-infinite horizontal plate with temperature dependent viscosity. The mass transfer with chemically reactive species for two classes of viscoelastic fluid over a porous stretching sheet is discussed by Cortell [12]. Andersson et al. [13] discussed the

The study of MHD fluid flow in porous and non-porous medium has attracted the attention of many researchers because of its abundant application in diverse fields of science and technology. Abbas and Palani [1] examined the effects of magnetohydrodynamic flow past a vertical plate with variable surface temperature. Arpaci [4] reported on the effects of thermal radiation on the laminar free convection from a heated vertical plate. Badruddin et al. [5] investigated free convection and radiation characteristics for a vertical plate embedded in a porous medium. They discussed the flow of water through different porous media under different environmental conditions. The

Nanofluids are another sort of warmth exchange medium, containing nanoparticles (1–100 nm), which are consistently and steadily distributed in a base liquid (Wang & Mujumdar, 2007). Down scaling or scaling down has been a late major pattern in cutting edge science and innovation. Builds now manufacture miniaturized scale gadgets, for example, micro channel heat exchangers, and small-scale pumps that are the measure of dust bits. Further significant advances would be gotten if the coolant streaming in the smaller scale channels were to contain nanoscale particles to upgrade heat exchange. Nanofluids innovation will in this way be a rising and energizing innovation of the 21st century. This paper gives explanation on the nanofluids technology and its performance advantages. It likewise depicts case of potential applications and characterizations of nanofluids. At long last, future examination on the fundamentals and utilizations of nanofluids are great (Wang & Mujumdar, 2007).

Phase change materials are widely used source of thermoregulation (TM) systems and in latent thermal energy storage (LTES). PCMs capability to absorb and release large latent heat during phase change transition processes provides a wide range of phase change temperatures for thermal management systems. The incorporation of PCMs can achieve the same or even better performances with a smaller volume. PCMs can meet the thermoregulation requirements of various applications. Currently, the low thermal conductivity of PCMs (usually less than 1 W mK−1) greatly limits their heat dissipation performance in thermal management applications. Currently main focus of research is to increase the thermal conductivity of the PCMs. In this regard different kinds of materials such as metal and carbon composites with PCMs are produced. The intensive experimental and theoretical investigation are made to improve the performance of PCMs. This paper discusses in detail the fabrication and thermal conductance measurement techniques, and mathematical modeling of PCMs composites. Moreover applications of PCMs in TM and LTES system are also mentioned with examples.

In this paper, three-dimensional water and Al2O3-water nano fluid flow and heat transfer is optimized geometrically using constructal theory. A numerical code based on the finite volume method and SIMPLER algorithm is developed to solve the governing equations. The code is carefully validated by comparing numerical predictions with experimental data. In this study we consider aspect ratio, number of channels in the heat sink and solid fraction factor as degrees of freedom. Given a specific volume and axial length of the micro channel heat sinks and a fixed pressure drop, we want to find out the best possible number of channels in the system, and geometry of each channel that maximizes the global thermal conductance. Furthermore we investigate the effect of different pressure drops. The results show that the geometric parameters have a strong effect on the performance of micro channel heat sink. Comparison of the results of water and Al2O3-water nano fluid indicate that neither Re nor pressure drop along the channel are good parameters to compare the thermal performance of nano fluid and water.