Spelling suggestions: "subject:"bechanical energy"" "subject:"bechanical anergy""
1 |
Control of coal flow in pressurized vertical spindle mills with four outlet pipes.Koroglu, Can. January 2009 (has links)
Thesis (M.S.)--Lehigh University, 2009. / Adviser: Edward K. Levy.
|
2 |
Hydraulic impacts of hydrokinetic energy extraction in riversKartezhnikova, Maria 11 February 2014 (has links)
<p> A simple technique to estimate the hydraulic impacts associated with the deployment of hydrokinetic (HK) devices is introduced. This technique involves representing HK devices with an enhanced bottom roughness. The enhanced bottom roughness is found to be a function of Manning roughness, slope, and water depth of the natural channel as well as device efficiency, blockage ratio, and density of device deployment. This approach was developed using a theoretical relationship between power extracted to power dissipated, and assuming a simple rectangular channel cross-section and uniform distribution of devices. Once the effective bottom roughness is determined, it can be used to determine the hydraulic impact of arbitrary device configurations and flow situations. The enhanced bottom roughness approach was compared to an alternative method of determining the affects of hydrokinetic energy extraction (SNL-EFDC). Both methods were in good agreement. Capabilities and limitations of determining hydraulic impacts by enhanced bottom roughness approach are demonstrated by site-specific simulation for the Tanana site. </p>
|
3 |
Caracterisation numerique et experimentale d'une cellule ventilee et chauffee par plinthe electrique ou par panneau radiant.Lariani, Abdessalem. Unknown Date (has links)
Thèse (M.Sc.A.)--Université de Sherbrooke (Canada), 2008. / Titre de l'écran-titre (visionné le 1 février 2007). In ProQuest dissertations and theses. Publié aussi en version papier.
|
4 |
Etude du cycle transcritique en dimensions finies utilisant le dioxyde de carbone comme fluide moteur avec des rejets de faible temperature comme source de chaleur.Cayer, Emmanuel. Unknown Date (has links)
Thèse (M.Sc.A.)--Université de Sherbrooke (Canada), 2008. / Titre de l'écran-titre (visionné le 1 février 2007). In ProQuest dissertations and theses. Publié aussi en version papier.
|
5 |
Comparing the effectiveness of heat rate improvements in different coal-fired power plants utilizing carbon dioxide capture.Walsh, Martin Jeremy. January 2010 (has links)
Thesis (M.S.)--Lehigh University, 2010. / Adviser: Edward K. Levy.
|
6 |
Caractérisation numérique et expérimentale d'une cellule ventilée et chauffée par plinthe électrique ou par panneau radiantLariani, Abdessalem. January 2007 (has links)
Thèse (M.Sc.A.)--Université de Sherbrooke (Canada), 2007. / Titre de l'écran-titre (visionné le 1 février 2007). In ProQuest dissertations and theses. Publié aussi en version papier.
|
7 |
Impact of Radon Ventilation on Indoor Air Quality and Building Energy savingAkbari, Keramatollah January 2009 (has links)
<p>Industrial living is caused much people do live and work in closed and confined places; offices and residential buildings. This is why in this new world more fresh air which is generally provided by forced ventilation plays a vital role in living of human being. Furthermore because of many different indoor pollutants, like radon and artificial pollutants, the amount of fresh air and in turn the energy consumption has increased. This energy consumption related to ventilation has reached up to about 30 percent of energy used of building section. So making interaction between indoor air quality (IAQ) and optimization of energy saving is a necessary work. Radon as a natural pollutant is occurred in environment and in many countries threatens people health whereas is called the second causes of cancer. For reducing radon concentration in residential building at the acceptable level forced ventilation is used usually. Ventilation can improve IAQ but in the other side would increase the energy consumption in building sector and just now the contribution of ventilation exceeds up 50 percent of building sector's share. The aim of this thesis is to study the impact of ventilation on indoor radon by using Computational Fluid Dynamics (CFD) to achieve indoor air quality and energy efficiency. Application of CFD as a new technology, because of its cost and time savings, and on the other side, of its flexibility and precision is increasingly grown and can be used as a very important and valuable tool for the prediction and measurement of radon distribution in a ventilated building . Currently, measurement techniques and proposed standards and regulations of indoor pollutants and ventilation, particularly related to indoor radon cannot be able to provide a secure, safe and energy efficient indoor climate. This is why the indoor airflow distribution is very complex and with changing building geometry and operation condition, the treatment of air flow pattern, substantially would be changed, whereas the rules are usually independent of the buildings features. Furthermore, the indoor standards and regulations are based on average amount of pollutants in a room, whereas the pollutant distributions aren't identical and are varied throughout the room. Then the current techniques aren't so exactly valuable and acceptable.</p><p>From different methods which is privilege to control pollutants, ventilation method is applicable in existing buildings. Designing effective ventilation can reduce radon concentration to very level low with regarding energy conservation remarks.</p><p> </p><p>This thesis presents results from simulation studies on ventilation and radon mitigation in residential buildings, in view points of indoor air quality and energy savings. The CFD technique is applied to predict, visualize and calculate of mixture radon-air flow. The distribution of indoor radon concentration, air velocity and room temperature also have considered together for achieving indoor air quality and energy saving. The results are also compared with the experimental data and related previous works.</p><p> </p><p>It was found that with increasing ventilation rate, the radon concentration is decreased, but the location of ventilation system is also important. From the simulation results, it is observed that within the ventilated room, there are some zones, which are good for living and somewhere is more polluted. The traditional radon detectors basically show the average value of radon content in 1m<sup>3</sup> of air. That is why detector measuring is not exact and safe.</p><p> </p><p>Simulation results proved that floor heat can be supported ventilation effect and speed up the mixture movement. Floor heating reinforces the buoyancy effect, which is useful to reduce radon content in the floor (seating area) and then lower ventilation rate can be applied.</p>
|
8 |
Analysis of a new district heating line : Evaluation of heat losses and hydraulic facilitiesSanchez, Javier January 2008 (has links)
<p>The aim of the project is to analyze the enlargement of the district heating line located in Gävle, evaluating the hydraulic facilities and calculating the heat losses with different insulation thicknesses to choose the best insulation thickness for the pipes. To choose the best thickness, different insulation thicknesses have been evaluated calculating the heat losses for each insulation thickness. To manage the heat losses problem, the pipe length has been divided into three</p><p>stretches, underground pipe, sea pipe and air pipe. These three stretches have different boundary conditions, and each stretch has been calculated separately. The best thermal solution is choosing the insulation of 0.5m of thickness, but the best thermal solution is not the best solution for this project due to the elevated cost of this thickness in one of the stretches of the line. The pipe crossing the seahas to be on the bottom and to keep the pipe on the bottom concrete is going to be added. The quantity of concrete needed depends on the floatability of the pipe and specifically depends on the insulation thickness. The insulation is a porous material and its density is very small, therefore it has a high floatability. The final</p><p>selection is a multi-thickness insulation, with different insulation thicknesses in the different stretches, 0.6m of thickness in the underground and air pipe and 0.3m of thickness in the sea pipe. With this configuration the heat losses are quite close to the optimum case. The purpose in the hydraulic study has been quantifying the start pressure in the new line to fulfil the energy demand in the worst point of the line. With 320kPa at the start of line, the pressure in the worst point is enough to fulfil the nowadays</p><p>demand, 3MW, and in the future when this line will be enlarged and the demand increased to 20MW, the pressure at the start of the line to ensure the requested pressure of 250kPa in the worst point should reach more than 380kPa. Having such pressure is not recommended to avoid the pressure hammer and to build a new pumping station after the sea pipe is recommended.</p>
|
9 |
Impact of Radon Ventilation on Indoor Air Quality and Building Energy savingAkbari, Keramatollah January 2009 (has links)
Industrial living is caused much people do live and work in closed and confined places; offices and residential buildings. This is why in this new world more fresh air which is generally provided by forced ventilation plays a vital role in living of human being. Furthermore because of many different indoor pollutants, like radon and artificial pollutants, the amount of fresh air and in turn the energy consumption has increased. This energy consumption related to ventilation has reached up to about 30 percent of energy used of building section. So making interaction between indoor air quality (IAQ) and optimization of energy saving is a necessary work. Radon as a natural pollutant is occurred in environment and in many countries threatens people health whereas is called the second causes of cancer. For reducing radon concentration in residential building at the acceptable level forced ventilation is used usually. Ventilation can improve IAQ but in the other side would increase the energy consumption in building sector and just now the contribution of ventilation exceeds up 50 percent of building sector's share. The aim of this thesis is to study the impact of ventilation on indoor radon by using Computational Fluid Dynamics (CFD) to achieve indoor air quality and energy efficiency. Application of CFD as a new technology, because of its cost and time savings, and on the other side, of its flexibility and precision is increasingly grown and can be used as a very important and valuable tool for the prediction and measurement of radon distribution in a ventilated building . Currently, measurement techniques and proposed standards and regulations of indoor pollutants and ventilation, particularly related to indoor radon cannot be able to provide a secure, safe and energy efficient indoor climate. This is why the indoor airflow distribution is very complex and with changing building geometry and operation condition, the treatment of air flow pattern, substantially would be changed, whereas the rules are usually independent of the buildings features. Furthermore, the indoor standards and regulations are based on average amount of pollutants in a room, whereas the pollutant distributions aren't identical and are varied throughout the room. Then the current techniques aren't so exactly valuable and acceptable. From different methods which is privilege to control pollutants, ventilation method is applicable in existing buildings. Designing effective ventilation can reduce radon concentration to very level low with regarding energy conservation remarks. This thesis presents results from simulation studies on ventilation and radon mitigation in residential buildings, in view points of indoor air quality and energy savings. The CFD technique is applied to predict, visualize and calculate of mixture radon-air flow. The distribution of indoor radon concentration, air velocity and room temperature also have considered together for achieving indoor air quality and energy saving. The results are also compared with the experimental data and related previous works. It was found that with increasing ventilation rate, the radon concentration is decreased, but the location of ventilation system is also important. From the simulation results, it is observed that within the ventilated room, there are some zones, which are good for living and somewhere is more polluted. The traditional radon detectors basically show the average value of radon content in 1m3 of air. That is why detector measuring is not exact and safe. Simulation results proved that floor heat can be supported ventilation effect and speed up the mixture movement. Floor heating reinforces the buoyancy effect, which is useful to reduce radon content in the floor (seating area) and then lower ventilation rate can be applied.
|
10 |
Numerical Analysis of Partial Admission in Axial TurbinesBaagherzadeh Hushmandi, Narmin January 2010 (has links)
HTML clipboard Numerical analysis of partial admission in axial turbines is performed in this work. Geometrical details of an existing two stage turbine facility with low reaction blades is used for this purpose. For validation of the numerical results, experimental measurements of one partial admission configuration at design point was used. The partial admission turbine with single blockage had unsymmetrical shape; therefore the full annulus of the turbine had to be modeled numerically. The numerical grid included the full annulus geometry together with the disc gaps and rotor shrouds. Importance of various parameters in accurate modeling of the unsteady flow field of partial admission turbines was assessed. Two simpler models were selected to study the effect of accurate modeling of radial distribution of flow parameters. In the first numerical model, the computational grid was two dimensional and the radial distribution of flow parameters was neglected. The second case was three-dimensional and full blades’ span height was modeled but the leakage flows at disc cavity and rotor shroud were neglected. Detailed validation of the results from various computational models with the experimental data showed that modeling of the leakage flow at disc cavities and rotor shroud of partial admission turbines has substantial importance in accuracy of numerical computations. Comparison of the results from two computational models with varying inlet extension showed that modeling of the inlet cone has considerable importance in accuracy of results but with increased computational cost. Partial admission turbine with admission degree of ε = 0.524 in one blocked arc and two opposing blocked arcs were tested. Results showed that blocking the inlet annulus in one single arc produce better overall efficiency compared to the two blocked arc model. Effect of varying axial gap distance between the first stage stator and rotor rows was also tested numerically for the partial admission turbine with admission degree of ε = 0.726. Results showed higher efficiency for the reduced axial gap model. Computations showed that the main flow leave the blade path down to the disc cavity and re-enter into the flow channel downstream the blockage, this flow would pass the rotor with very low efficiency. First stage rotor blades are subject to large unsteady forces due to the non-uniform inlet flow. Plotting the unsteady forces of first stage rotor blades for partial admission turbine with single blockage showed that the blades experience large changes in magnitude and direction while traveling along the circumference. Unsteady forces of first stage rotor blades were plotted in frequency domain using Fourier transform. The largest amplitudes caused by partial admission were at first and second multiples of rotational frequency due to the existence of single blockage and change in the force direction. Results obtained from the numerical computations showed that the discs have nonuniform pressure distribution especially in the first stage of partial admission turbines. The axial force of the first rotor wheel was considerably higher when the axial gap distance was reduced between the first stage stator and rotor rows. The commercial codes used in this work are ANSYS ICEM-CFD 11.0 as mesh generator and FLUENT 6.3 as flow solver. / QC20100622
|
Page generated in 0.0427 seconds