scholarly journals Improving Thermal Analysis Accuracy of LPTN for Vehicle Claw-Pole Alternator by Calibrating Forced Convection Coefficients Based on Experimental Results

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 129327-129334 ◽  
Author(s):  
Ming Li ◽  
Yuejun An ◽  
Zhiheng Zhang
Keyword(s):  
Thermal Analysis ◽  
Forced Convection ◽  
Experimental Results

scholarly journals An Experimental Study of the Decomposition and Carbonation of Magnesium Carbonate for Medium Temperature Thermochemical Energy Storage

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1316
Author(s):  
Daniel Mahon ◽  
Gianfranco Claudio ◽  
Philip Eames
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Energy Storage ◽  
Magnesium Carbonate ◽  
Experimental Results ◽  
Future Research ◽  
Medium Temperature ◽  
Different Temperatures ◽  
Decomposition Enthalpy ◽  
Co2 Atmosphere

To improve the energy efficiency of an industrial process thermochemical energy storage (TCES) can be used to store excess or typically wasted thermal energy for utilisation later. Magnesium carbonate (MgCO3) has a turning temperature of 396 °C, a theoretical potential to store 1387 J/g and is low cost (~GBP 400/1000 kg). Research studies that assess MgCO3 for use as a medium temperature TCES material are lacking, and, given its theoretical potential, research to address this is required. Decomposition (charging) tests and carbonation (discharging) tests at a range of different temperatures and pressures, with selected different gases used during the decomposition tests, were conducted to gain a better understanding of the real potential of MgCO3 for medium temperature TCES. The thermal decomposition (charging) of MgCO3 has been investigated using thermal analysis techniques including simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), TGA with attached residual gas analyser (RGA) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (up to 650 °C). TGA, DSC and RGA data have been used to quantify the thermal decomposition enthalpy from each MgCO3.xH2O thermal decomposition step and separate the enthalpy from CO2 decomposition and H2O decomposition. Thermal analysis experiments were conducted at different temperatures and pressures (up to 40 bar) in a CO2 atmosphere to investigate the carbonation (discharging) and reversibility of the decarbonation–carbonation reactions for MgCO3. Experimental results have shown that MgCO3.xH2O has a three-step thermal decomposition, with a total decomposition enthalpy of ~1050 J/g under a nitrogen atmosphere. After normalisation the decomposition enthalpy due to CO2 loss equates to 1030–1054 J/g. A CO2 atmosphere is shown to change the thermal decomposition (charging) of MgCO3.xH2O, requiring a higher final temperature of ~630 °C to complete the decarbonation. The charging input power of MgCO3.xH2O was shown to vary from 4 to 8136 W/kg with different isothermal temperatures. The carbonation (discharging) of MgO was found to be problematic at pressures up to 40 bar in a pure CO2 atmosphere. The experimental results presented show MgCO3 has some characteristics that make it a candidate for thermochemical energy storage (high energy storage potential) and other characteristics that are problematic for its use (slow discharge) under the experimental test conditions. This study provides a comprehensive foundation for future research assessing the feasibility of using MgCO3 as a medium temperature TCES material. Future research to determine conditions that improve the carbonation (discharging) process of MgO is required.

Methyl Trichlorosilane Prepared Methyl Sodium Silicate

2012 ◽  
Vol 184-185 ◽  
pp. 1064-1067
Author(s):  
Guang Xia Zhang ◽  
Qiao Yun Zhang ◽  
Ze Min Chen
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Water Solubility ◽  
Experimental Results ◽  
White Powder ◽  
Molten State

This paper studied how to prepare Methyl Sodium Silicate from Methyl Trichlorosilane. Methyl trichlorosilane hydrolyzed on the interface of cyclohexane and water, then hydrolysate and sodium hydroxide prepared methyl sodium silicate at molten state. Manufactrue was characterised by XRD, IR, and differential thermal analysis. The experimental results indicate that the best hydrolyze condition was the proportion of methyl trichlorosilane and water was 10~12:100 , at 5°C, lasting for 45min; the best condition of prepared methyl sodium silicate was the proportion of sodium hydroxide and hydrolysate was 2.1~2.3:1, at 300 ~450°C, lasting for 50min. The manufacture was white powder, water-solubility and well stabilization bellow 450°C.

Experimental Study on Forced Convection Heat Transfer Inside Horizontal Tubes in an Absorption/Compression Heat Pump

2002 ◽  
Vol 124 (5) ◽  
pp. 975-978 ◽  
Author(s):  
Li Yong and ◽  
K. Sumathy
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Forced Convection ◽  
Experimental Results ◽  
Working Fluid ◽  
Large Temperature ◽  
Absorption Process ◽  
Transfer Coefficients ◽  
Tube Heat Exchanger ◽  
Heat Transfer Coefficients

Quasi-local absorption heat transfer coefficients and pressure drop inside a horizontal tube absorber have been investigated experimentally, with R-22/DMA as the working pair. The absorber is a counterflow coaxial tube-in-tube heat-exchanger with the working fluid flowing in the inner tube while the water moves through the annulus. A large temperature gliding has been experienced during the absorption process. Experimental results show that the heat transfer coefficient of the forced convective vapor absorption process is higher compared to the vertical falling film absorption. A qualitative study is made to analyze the effect of mass flux, vapor quality and solution concentration on pressure drop and heat transfer coefficients. On the basis of the experimental results, a new correlation is proposed whereby the two-phase heat transfer is taken as a product of the forced convection of the absorption and the combined effect of heat and mass transfer at the interface. The correlation is found to predict the experimental data almost within 30 percent.

Custom 1-D CFD Numeric Model of Single-Cell Scale Sample Holder for Scanning Thermal Analysis

2012 ◽  
Author(s):  
Logan M. Compton ◽  
James L. Armes ◽  
Gary L. Solbrekken
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Latent Heat ◽  
Thermoelectric Module ◽  
Experimental Results ◽  
Sample Holder ◽  
Current Profile ◽  
Scanning Calorimetry ◽  
Numeric Model

Successful cryopreservation protocols have been developed for a limited number of cell types through an extensive amount of experimentation. To optimize current protocols and to develop effective protocols for a larger range of cells and tissues it is imperative that accurate transport models be developed for the cooling process. Such models are dependent on the thermodynamic properties of intracellular and extracellular solutions, including heat capacity, latent heat, and the physical phase change temperatures. Scanning techniques, such as differential-scanning calorimetry (DSC) and differential thermal analysis are effective tools for measuring those thermodynamic properties. It is essential to understand the behavior of the in house fabricated differential-scanning calorimeter given different cooling and warming rates to reassure and validate the obtained experimental results. A 1-D transient CFD code was created in Matlab using Patankar’s theory to not only validate obtained experimental results but aid in optimizing the control system to produce linear cooling and warming rates. A freezing model was also implemented as a subroutine to numerically observe the effect of heat release and absorption of the sample during a run. The numeric model is composed of a multilayer scheme that incorporates a thermoelectric module which provides the primary temperature control along with the micron sized bridge with sample holder and thermocouple. An electric current profile is imported in from either an experimental run to validate results or from an optimization program to determine the optimum electrical current profile for a desired temperature profile. Numeric detection of heat capacity, latent heat, and thermal resistance has also been demonstrated.

Integrated Micro-Channel Cooling in Industrial Applications

2004 ◽  
Author(s):  
C. C. S. Nicole ◽  
R. Dekker ◽  
A. Aubry ◽  
R. Pijnenburg
Keyword(s):  
Forced Convection ◽  
Flow Rate ◽  
Single Phase ◽  
Industrial Applications ◽  
Experimental Results ◽  
Junction Temperature ◽  
Micro Channel ◽  
Cooling Device ◽  
Micro Channels ◽  
Cooling Of Electronics

Experiments and simulations have been performed in order to assess the feasibility of integrated single phase forced convection in silicon micro-channels for the cooling of electronics. A silicon micro-channel device has been fabricated with channel size of 100 by 300 μm. Cooling has been achieved with a heater dissipating up to 370 W (750 W/cm2) with a flow rate of 0.1 1/min. In this case the maximum junction temperature was 130°C. This paper presents characteristics of such a cooling device as well as its description and fabrication. Experimental results are shown and compared with simulations. A description of a rough optimization of the channels size is given followed by comments describing the main advantages and drawbacks regarding industrial feasibility.

Finned Metal Foam Heat Sinks for Electronics Cooling in Forced Convection

2002 ◽  
Vol 124 (3) ◽  
pp. 155-163 ◽  
Author(s):  
A. Bhattacharya ◽  
R. L. Mahajan
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Forced Convection ◽  
Metal Foam ◽  
Experimental Results ◽  
Heat Sinks ◽  
The Heat Transfer Coefficient

In this paper, we present recent experimental results on forced convective heat transfer in novel finned metal foam heat sinks. Experiments were conducted on aluminum foams of 90 percent porosity and pore size corresponding to 5 PPI (200 PPM) and 20 PPI (800 PPM) with one, two, four and six fins, where PPI (PPM) stands for pores per inch (pores per meter) and is a measure of the pore density of the porous medium. All of these heat sinks were fabricated in-house. The forced convection results show that heat transfer is significantly enhanced when fins are incorporated in metal foam. The heat transfer coefficient increases with increase in the number of fins until adding more fins retards heat transfer due to interference of thermal boundary layers. For the 20 PPI samples, this maximum was reached for four fins. For the 5 PPI heat sinks, the trends were found to be similar to those for the 20 PPI heat sinks. However, due to larger pore sizes, the pressure drop encountered is much lower at a particular air velocity. As a result, for a given pressure drop, the heat transfer coefficient is higher compared to the 20 PPI heat sink. For example, at a Δp of 105 Pa, the heat transfer coefficients were found to be 1169W/m2-K and 995W/m2-K for the 5 PPI and 20 PPI 4-finned heat sinks, respectively. The finned metal foam heat sinks outperform the longitudinal finned and normal metal foam heat sinks by a factor between 1.5 and 2, respectively. Finally, an analytical expression is formulated based on flow through an open channel and incorporating the effects of thermal dispersion and interfacial heat transfer between the solid and fluid phases of the porous medium. The agreement of the proposed relation with the experimental results is promising.

Sign in / Sign up

Export Citation Format

Share Document