The Stirring and Heating CFD Simulation Strategic Research on Food Waste Biological Treatment Processor

2012 ◽  
Vol 268-270 ◽  
pp. 992-996
Author(s):  
De Yu Song ◽  
Song Lin
Keyword(s):  
Heat Pipe ◽  
Food Waste ◽  
Biological Treatment ◽  
Cfd Simulation ◽  
Heating Effect ◽  
Processing Efficiency ◽  
Strategic Research ◽  
Solar Heat ◽  
Turbulent Mode

By analysis the physics parameter of food waste, considering about using CFD technology for the stirring and heating simulation strategic research, guides the stirring structure and heating effect design.Focus on the three layers horizontal paddle Stirring processor’s dealing process for the entity modeling, and considering using MRF method, choosing the Low-Re RNG-κ-ε turbulent mode, heating from the surround of the equipment, meanwhile by insert one solar heat pipe into the middle shaft for the simulation strategic research. The research has actual guidance significance on how to improve the processing efficiency.

Experimental and Numerical Simulation for Thermal Investigation of Oscillating Heat Pipe Using VOF Model

2020 ◽  
Vol 38 (1A) ◽  
pp. 88-104
Author(s):  
Anwar S. Barrak ◽  
Ahmed A. M. Saleh ◽  
Zainab H. Naji
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Heat Input ◽  
Cfd Simulation ◽  
Working Fluid ◽  
Maximum Deviation ◽  
Inlet Temperature ◽  
Maximum Heat ◽  
Oscillating Heat Pipe ◽  
Vof Model

This study is investigated the thermal performance of seven turns of the oscillating heat pipe (OHP) by an experimental investigation and CFD simulation. The OHP is designed and made from a copper tube with an inner diameter 3.5 mm and thickness 0.6 mm and the condenser, evaporator, and adiabatic lengths are 300, 300, and 210 mm respectively.  Water is used as a working fluid with a filling ratio of 50% of the total volume. The evaporator part is heated by hot air (35, 40, 45, and 50) oC with various face velocity (0.5, 1, and 1.5) m/s. The condenser section is cold by air at temperature 15 oC. The CFD simulation is done by using the volume of fluid (VOF) method to model two-phase flow by conjugating a user-defined function code (UDF) to the FLUENT code. Results showed that the maximum heat input is 107.75 W while the minimum heat is 13.75 W at air inlet temperature 35 oC with air velocity 0.5m/s. The thermal resistance decreased with increasing of heat input. The results were recorded minimum thermal resistance 0.2312 oC/W at 107.75 W and maximum thermal resistance 1.036 oC/W at 13.75W. In addition, the effective thermal conductivity increased due to increasing heat input.  The numerical results showed a good agreement with experimental results with a maximum deviation of 15%.

Comparative Performance of Two Prototypes of a Passive Solar Heat Pipe System

2014 ◽  
Author(s):  
Brian S. Robinson ◽  
M. Keith Sharp
Keyword(s):  
Heat Pipe ◽  
Test Facility ◽  
Reverse Direction ◽  
Storage Tanks ◽  
New Model ◽  
Solar Heat ◽  
Pipe System ◽  
Evaporator Section ◽  
Passive Solar ◽  
New System

Thermal performance of an improved passive solar heat pipe system was directly compared to that of a previous prototype. Simulated and experimental results for the first prototype established baseline performance. Subsequently, potential improvements were simulated, and a second prototype was built and tested along side the first. The system uses heat pipes for high rates of heat transfer into the building, and limited losses in the reverse direction. The evaporator section of each heat pipe is attached to a glass-covered absorber on the outside of a south wall, and the slightly elevated condenser section is either immersed in water in a thermal storage tank or exposed to air in the room. Two-phase flow occurs in the heat pipe only when the evaporator is warmer than the condenser, creating a thermal diode effect. Computer simulations showed that system performance could be improved by using thicker insulation between the absorber and the storage tanks, and by switching from a copper to a rubber adiabatic section, which both reduced heat losses to ambient from the storage tanks. Early morning heating was improved by exposing one of five condensers directly to room air, which also improved overall system efficiency. A copper solar absorber soldered to the copper evaporator section improved heat conduction compared to the previous aluminum absorber bonded to the copper evaporator. Together these modifications improved simulated annual solar fraction by 20.8%. The new prototype incorporating these changes was tested along side the previous prototype in a two-room passive solar test facility during January through February of 2013. Temperatures were monitored with thermocouples at multiple locations throughout the systems, in each room and outdoors. Insolation was measured by four pyranometers attached to the building. Results showed that the design modifications implemented for the new model increased thermal gains to storage and to the room, and decreased thermal losses to ambient. The load-to-collector ratio for the experiments was 2.7 times lower than for the simulations, which decreased the potential for experimental improvements compared to the simulated improvements. However, average daily peak efficiency for the new system was 85.0%, compared to 80.7% for the previous system. Furthermore, the average storage temperature over the entire testing period for the new model was 13.4% higher than that of the previous model, while the average room temperature over the same period was 24.6% greater for the new system.

Gas chromatographic analysis of polychlorinated biphenyls in compost samples from different origin

2019 ◽  
Vol 37 (5) ◽  
pp. 556-562 ◽  
Author(s):  
Karolina Barcauskaitė
Keyword(s):  
Sewage Sludge ◽  
Polychlorinated Biphenyls ◽  
Organic Pollutants ◽  
Food Waste ◽  
Persistent Organic Pollutants ◽  
Biological Treatment ◽  
Cattle Manure ◽  
Municipal Waste ◽  
Green Waste ◽  
Municipal Waste Compost

Depending on the origin, the compost produced may contain not only nutrients but also pollutants, such as heavy metals and persistent organic pollutants. It is very important to determine them in soil-improving substances, because persistent organic pollutants show environmental toxic, cancerogenic, mutagenic effects and do not decompose for a long time. The aim of this study was to determine seven polychlorinated biphenyls concentrations in different kinds of composts produced in Lithuania and to evaluate the appliance of these composts in agricultural land. First, before routine analysis was done a gas chromatography with electron-capture detector method was developed. In this study 145 samples of green waste, sewage sludge, cattle manure, food waste, mixed municipal waste, digestate and composts made from mixed municipal waste after mechanical–biological treatment were analysed. Obtained results show that 28% of investigated cattle manure composts (CMCs) and 10.5% of food waste composts (FWCs) were free from polychlorinated biphenyls. Other kinds of composts investigated in this study (green waste compost (GWC), sewage sludge compost (SSC), mixed municipal waste compost (MMWC), mixed municipal waste compost after mechanical biological treatment (MMWCABMT) and digestate (DIG)) were contaminated 100% with polychlorinated biphenyls. Despite the fact that polychlorinated biphenyls were forbidden 25 years ago, their concentration varied from 2.70 to 163.7 µg kg−1 in different kinds of composts produced in Lithuania. According to get an increasing average amount of Σ7 polychlorinated biphenyls, Lithuanian composts were distributed as follows CMC > GWC > DIG > FWC > SSC > MMWCABMT > MMWC.

Solar Load Ratio Parameters for a Passive Solar Heat Pipe System

2015 ◽  
Author(s):  
Logan S. Poteat ◽  
M. Keith Sharp
Keyword(s):  
Heat Pipe ◽  
Load Ratio ◽  
Building Design ◽  
Weather Data ◽  
Prediction Algorithm ◽  
Solar Heat ◽  
Pipe System ◽  
Thermal Network ◽  
Pipe Systems ◽  
Passive Solar

The Solar Load Ratio (SLR) method is a performance prediction algorithm for passive solar space heating systems developed at Los Alamos National Laboratory. Based on curve fits of detailed thermal simulations of buildings, the algorithm provides fast estimation of monthly solar savings fraction for direct gain, indirect gain (water wall and concrete wall) and sunspace systems of a range of designs. Parameters are not available for passive solar heat pipe systems, which are of the isolated gain type. While modern computers have increased the speed with which detailed simulations can be performed, the quick estimates generated by the SLR method are still useful for early building design comparisons and for educational purposes. With this in mind, the objective of this project was to develop SLR predictions for heat pipe systems, which use heat pipes for one-way transport of heat into the building. A previous thermal network was used to simulate the heat pipe system with Typical Meteorological Year (TMY3) weather data for 13 locations across the US, representing ranges of winter temperature and available sunshine. A range of (nonsolar) load-to-collector ratio LCR = 1–15 W/m2K was tested for each location. The thermal network, along with TMY3 data, provided monthly-average-daily absorbed solar radiation and building load to calculate SLR. Losses from the solar aperture in a heat pipe system are very low compared to conventional passive solar systems, thus the load-to-collector ratio of the solar aperture was neglected in these preliminary calculations. Likewise, nighttime insulation is unnecessary for a heat pipe system, and was not considered. An optimization routine was used to determine an exponential fit (the heart of the SLR method) to simulated monthly solar savings fraction (SSF) across all locations and LCR values. Accuracy of SSF predicted by SLR compared to the thermal network results was evaluated. The largest errors (up to 50%) occurred for months with small heating loads (< 80 K days), which inflated SSF. Limiting the optimization to the heating season (October to March), reduced the error in SSF to an average of 4.24% and a standard deviation of 5.87%. These results expand the applications of the SLR method to heat pipe systems, and allow building designers to use this method to estimate the thermal benefits of heat pipe systems along with conventional direct gain, indirect gain and sunspace systems.

Experimental Investigation of a New Flat Plate Solar Heat Collector by Micro Heat Pipe Array

2010 ◽  
Author(s):  
Yao-Hua Zhao ◽  
Fei-Long Zou ◽  
Yan-Hua Diao ◽  
Zhen-Hua Quan
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
High Efficiency ◽  
Heat Pipes ◽  
Total Heat Loss ◽  
Solar Heat ◽  
Solar Water ◽  
Micro Heat Pipe ◽  
Heat Collector ◽  
Micro Heat Pipes

The performance of a new flat plate solar heat collector with perfect combination of high efficiency and low cost is investigated experimentally. The new system described in this study uses a novel micro heat pipe array as a key component for the system. One such flat plate heat collector contains over 300 micro heat pipes per 1m2 and the hydraulic diameter of the micro heat pipes is 0.4–1.0mm. A detailed heat transfer experimental study is conducted during daylight hours over several months, focusing on the collector efficiency and overall efficiency of the system as well as total heat loss factor. The results show that the collector’s maximum instantaneous efficiency is up to 88%. Compared with conventional evacuated glass tube solar water heater, the system offers the additional benefits of high pressure resistance, low weight, good reliability and durability, easy integration into buildings and absence of freezing during winter months. Besides, compared with traditional flat-plate solar water system which is mainly sheet-and-tube concept, the system also shows many advantages: higher efficiency, much cheaper, absence of tube-bonding and freezing etc. Therefore, the system proposes a unique substitute to common solar water heating systems.

scholarly journals Development of multi-evaporator loop heat pipe for solar heat utilization

2020 ◽  
Vol 2020 (0) ◽  
pp. 0027
Author(s):  
Naoki Ishida ◽  
Masahito Nishikawara ◽  
Hideki Yanada ◽  
Hiroshi Yokoyama
Keyword(s):  
Heat Pipe ◽  
Loop Heat Pipe ◽  
Solar Heat ◽  
Heat Utilization

scholarly journals Investigation of Solar Heat Pipe Collector Using Nanofluid and Surfactant

2016 ◽  
Vol 90 ◽  
pp. 481-491 ◽  
Author(s):  
Gargee A. Pise ◽  
Sanjay S. Salve ◽  
Ashok T. Pise ◽  
Amey A. Pise
Keyword(s):  
Heat Pipe ◽  
Solar Heat
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