Theoretical and Experimental Investigation of a Novel Multistage Evacuated Solar Still

2005 ◽  
Vol 127 (3) ◽  
pp. 381-385 ◽  
Author(s):  
Yousif A. Abakr ◽  
Ahmad F. Ismail
Keyword(s):  
Cfd Simulation ◽  
Condensation Process ◽  
Solar Still ◽  
Ambient Conditions ◽  
Element Analysis ◽  
Solar Desalination ◽  
Multi Stage ◽  
Low Efficiency ◽  
The Cost ◽  
New System

Solar desalination is an ideal source of fresh water for both drinking and agriculture. A lot of research was conducted on solar desalination systems, but most of the available systems have low production, are expensive, and are not reliable for long term use. In this work a new multistage evacuated solar desalination system was proposed and designed. The objective of this work is to increase the productivity and improve the low efficiency of the traditional solar desalination systems. The new system works by virtue of the higher evaporation rate under vacuum condition inside the solar still. A model for the system was developed and used to optimize the system design. The new model was subjected to a Finite Element Analysis (FEA) structural analysis using MSC/NASTRAN™ FEA software. A Computational Fluid Dynamics (CFD) simulation of the evaporation and condensation process inside one stage of the new solar still was conducted using FLUENT™ software. The system prototype was fabricated and tested at the actual outdoor ambient conditions for a period of 3 months. The productivity of this new system was found to be 14.2kg/m2/day, which is about threefold of the maximum productivity of the basin type solar still. The cost of produced still water is estimated as 0.20 US$/gal. The results show that the multi-stage evacuated solar still might be a good option as a solar desalination system.

Thermal Modeling, Experimental Validation, and Comparative Analysis of Modified Solar Stills

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Piyush Pal ◽  
Rahul Dev
Keyword(s):  
Comparative Analysis ◽  
Thermal Modeling ◽  
Uttar Pradesh ◽  
Solar Still ◽  
Solar Desalination ◽  
Low Efficiency ◽  
Basin Area ◽  
Evaluation Parameters ◽  
Theoretical Results ◽  
Good Agreement

AbstractIn the present work, an effort is carried out to enhance the distillate yield of a single-slope basin-type solar still by increasing the heat input through its transparent walls and providing hanging wicks to increase the evaporation–condensation rates. A modified basin-type single-slope multi-wick solar still (MBSSMWSS) was proposed and fabricated to increase the productivity and improve the low efficiency of the recently designed modified basin-type single-slope solar still (MBSSSS). Experiments were conducted on both the solar stills to assess their performance, productivity, and efficiency (thermal and exergy) for the same basin area and water depth for the climatic condition of Prayagraj, Uttar Pradesh (U.P.), India. Results showed that the productivity, overall energy (thermal) efficiency, and maximum values of measured instantaneous exergy efficiency of the MBSSSS and MBSSMWSS systems were found to be 3.2 l/m2 day and 4.22 l/m2 day, 18.16% and 26.89%, and 4.28% and 5.31%, respectively. Furthermore, thermal modeling was also done using the energy balance equations, and then, a theoretical analysis was carried out to validate with the respective experimental observations. A good agreement was found between experimental and theoretical results. Finally, based on the results of the evaluation parameters and comparative analysis, the modified solar still with wick was found to be a better system compared with that of the system without wick and might be a good option as a solar desalination system.

scholarly journals CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3934
Author(s):  
Federico Lluesma-Rodríguez ◽  
Temoatzin González ◽  
Sergio Hoyas
Keyword(s):  
Shock Waves ◽  
Power Consumption ◽  
High Speed ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Flow Behavior ◽  
Critical Conditions ◽  
Vehicle Speed ◽  
Blockage Ratio ◽  
The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

scholarly journals Experimental Validation of a Solar Powered Multistage Flash Desalination Unit with Alternate Storage Tanks

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2143
Author(s):  
Mishal Alsehli
Keyword(s):  
Water Resources ◽  
Solar Collector ◽  
Fossil Fuels ◽  
Feed Water ◽  
Daily Production ◽  
Solar Desalination ◽  
High Solar Radiation ◽  
Multi Stage ◽  
Tank Design ◽  
Solar Powered

The fossil fuels that power conventional desalination systems cause substantial environmental impact. Solar desalination can satisfy critical water needs with only a minimal contribution to global warming. The current work presents an attractive new design suitable for regions with limited water resources and high solar radiation rates. This work is an experimental study of a newly designed, solar-powered, multi-stage flash (MSF) desalination plant. The design could address the need to increase the limited water resources in solar energy-rich areas. The prototype consists of a solar collector, an MSF unit, and a novel dual thermal storage tank design. In this prototype, preheated brine is directly heated by circulation through the solar collector. Two tanks serve the MSF unit; one tank feeds the MSF unit while the other receives the preheated feed water. The two tanks alternate roles every 24 h. The study was conducted in Taif, Saudi Arabia, throughout the month of September 2020. The results of the experiment showed that 1.92 square meters of solar collector area is needed for an average daily production of 19.7 kg of fresh water, at a cost of approximately $0.015 per liter.

Solar desalination using solar still enhanced by PCM and nano fluid

2020 ◽  
Author(s):  
Karthikeyan Alagu ◽  
M. Siva Reddy ◽  
M. Narendra Kumar ◽  
Anderson Arul Gnana Dhas
Keyword(s):  
Solar Still ◽  
Nano Fluid ◽  
Solar Desalination

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

Finite Element Analysis of Composite Ceramic-Concrete Slab Constructions Exposed to Fire

2016 ◽  
Vol 861 ◽  
pp. 88-95
Author(s):  
Balázs Nagy ◽  
Elek Tóth
Keyword(s):  
Composite Structures ◽  
Elevated Temperatures ◽  
Cfd Simulation ◽  
Concrete Slab ◽  
Composite Ceramic ◽  
Reinforced Concrete Beam ◽  
Element Analysis ◽  
Standard Fire ◽  
Using Data ◽  
Dynamics Simulations

In this research, conjugated thermal and fluid dynamics simulations are presented on a modern hollow clay slab blocks filled pre-stressed reinforced concrete beam slab construction. The simulation parameters were set from Eurocode standards and calibrated using data from standardized fire tests of the same slab construction. We evaluated the temperature distributions of the slabs under transient conditions against standard fire load. Knowing the temperature distribution against time at certain points of the structure, the loss of load bearing capacity of the structure is definable at elevated temperatures. The results demonstrated that we could pre-establish the thermal behavior of complex composite structures exposed to fire using thermal and CFD simulation tools. Our results and method of fire resistance tests can contribute to fire safety planning of buildings.

Analysis of a Virtual Prototype First-Stage Rotor Blade Using Integrated Computer-Based Design Tools

2006 ◽  
Author(s):  
Michel Arnal ◽  
Christian Precht ◽  
Thomas Sprunk ◽  
Tobias Danninger ◽  
John Stokes
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Loading ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Life Assessment ◽  
Element Analysis ◽  
Pressure Losses ◽  
Cooling Channels ◽  
Internally Cooled

The present paper outlines a practical methodology for improved virtual prototyping, using as an example, the recently re-engineered, internally-cooled 1st stage blade of a 40 MW industrial gas turbine. Using the full 3-D CAD model of the blade, a CFD simulation that includes the hot gas flow around the blade, conjugate heat transfer from the fluid to the solid at the blade surface, heat conduction through the solid, and the coolant flow in the plenum is performed. The pressure losses through and heat transfer to the cooling channels inside the airfoil are captured with a 1-D code and the 1-D results are linked to the three-dimensional CFD analysis. The resultant three-dimensional temperature distribution through the blade provides the required thermal loading for the subsequent structural finite element analysis. The results of this analysis include the thermo-mechanical stress distribution, which is the basis for blade life assessment.

Efficient Solar Desalination System Using Humidification/Dehumidification Process

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Adel M. Abdel Dayem
Keyword(s):  
High Pressure ◽  
Heat Source ◽  
System Performance ◽  
Salt Water ◽  
Weather Conditions ◽  
Water Production ◽  
High Pressure Pump ◽  
Solar Desalination ◽  
Flat Plate Collector ◽  
The Cost

An innovative solar desalination system is successfully designed, manufactured, and experimentally tested at Makkah, 21.4 degN. The system consists of 1.15 m2 flat-plate collector as a heat source and a desalination unit. The unit is about 400 l vertical cylindrical insulated tank. It includes storage, evaporator, and condenser of hot salt-water that is fed from the collector. The heated water in the collector is raised naturally to the unit bottom at which it is used as storage. A high pressure pump is used to inject the water vertically up through 1-mm three nozzles inside the unit. The hot salt-water is atomized inside the unit where the produced vapor is condensed on the inner surfaces of the unit outer walls to outside. The system was experimentally tested under different weather conditions. It is obtained that the system can produce about 9 l a day per quadratic meter of collector surface area. By that it can produce about 1.6 l/kWh of solar energy. Moreover, the water temperature has a great effect on the system performance although the scaling possibility is becoming significant. By that way the cost of a liter water production is relatively high and is obtained as 0.5 US$.

CFD Simulation of Fluid Flow Through Porous Media: Application to Decomposed Gases Flow Through Foam Pattern in Lost Foam Casting

Materials ◽  
2003 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Phase Flow ◽  
Flow Through Porous Media ◽  
Foam Material ◽  
Element Analysis ◽  
Wide Range ◽  
Flow Through ◽  
Foam Pattern ◽  
Lost Foam

Numerical simulation of decomposed gases through foam pattern was conducted using finite element analysis. A new kinetic model is proposed for gaseos phase flow between molten metal and foam material. The computations were performed for a wide range of Reynolds numbers. The results of the simulations are compared with the experiemental data obtained in this study.

Flow Passage Modification and Experimental Verification of a Multi-Stage Centrifugal Pump

2013 ◽  
Vol 753-755 ◽  
pp. 2766-2769
Author(s):  
Quan Zhang ◽  
Zhi Jun Shuai ◽  
Pan Zhou ◽  
Wan You Li
Keyword(s):  
Centrifugal Pump ◽  
Cfd Simulation ◽  
Acceleration Response ◽  
Vibration Acceleration ◽  
Flow Passage ◽  
Fluid Field ◽  
Multi Stage ◽  
Through Flow ◽  
Seat Vibration ◽  
Velocity Pressure

In this paper the seat vibration acceleration response was reduced through flow passage modification of the centrifugal pump which could decrease the fluid excitation of the pump. CFD simulation technology was applied to optimize the fluid field of the multi-stage centrifugal pump, and then the velocity, pressure fluctuation and fluid excitation were concerned to investigate the effect of optimization. Finally, the influence of fluid field modification on the seat vibration response was verified experimentally.

Sign in / Sign up

Export Citation Format

Share Document