Advanced Search
Displaying 1-10 on page 1 of 443. Per Page  
  • Analysis of Bubble Behavior in a Horizontal Rectangular Channel under Subcooled Flow Boiling Conditions
  • Abstract Experiments on subcooled flow boiling have been conducted using water in a rectangular flow channel. Similar to the coolant channel in internal combustion engines (IC engines), the flow channel in this experiment was asymmetrically heated. Bubble images were captured using a high speed camera from the side view of the channel. The experimental conditions in terms of bulk temperature, bulk velocity, pressure and heat flux ranged from 65°C–75°C, 0.25 m/s–0.75 m/s, 1–1.7 bar and 490 kW/m2–700 kW/m2, respectively. On the basis of these tests, a statistical analysis of the bubble size has been conducted considering a population of 1400 samples.…
  • More
  •   Views:160       Downloads:187        Download PDF
  • Exergy Analysis and Thermal Optimization of a Double-Turbine Regeneration System in a Ultra-Supercritical Double-Reheat Unit
  • Abstract Improving the primary steam parameters is one of the most direct ways to improve the cycle efficiency of a power generation system. In the present study, the typical problem connected to the excessively high superheat degree of extraction steam in an ultra-supercritical (USC) double-reheat unit is considered. Using a 1000 MW power plant as an example, two systems (case 1 and case 2) are proposed, both working in combination with a regenerative steam turbine. The thermal performances of these two systems are compared with that of the original system through a heat balance method and an exergy balance strategy. The…
  • More
  •   Views:156       Downloads:160        Download PDF
  • Study on Energy Conversion Characteristics in Volute of Pump as Turbine
  • Abstract A volute is a curved funnel with cross-sectional area increasing towards the discharge port. The volute of a centrifugal pump is the casing hosting the fluid being pumped by the impeller. In Pump-as-turbine devices (PAT), vice versa the volute plays the role of energy conversion element. In the present analysis, this process is analyzed using CFD. The results show that in the contraction section of volute the conversion between dynamic pressure energy and static pressure energy essentially depends on the reduction of flow area, while in the spiral section, frictional losses also play a significant role. From the throat to…
  • More
  •   Views:153       Downloads:164        Download PDF
  • High-Density Block Transformation to Increase Natural Ventilation Based on CFD Simulation
  • Abstract Many countries in the world have experienced extremely rapid urbanization during recent decades. The rapid development of densely populated areas has produced many urban environmental problems. This research explores the relationship between urban morphology and ventilation conditions. Through 3D modeling and Computational Fluid Dynamics (CFD) simulation, we focus on the large scale ventilation of an extended area with several buildings. As a testbed, in particular, the core part of Kwun Tong industrial park in Hong Kong is examined, and in order to validate the approach, 10 measurement points are used to get experimental values to be used for comparison (such…
  • More
  •   Views:144       Downloads:150        Download PDF
  • Flow Simulation of a Horizontal Well with Two Types of Completions in the Frame of a Wellbore–Annulus–Reservoir Model
  • Abstract Well completions are generally used to connect a reservoir to the surface so that fluids can be produced from or injected into it. With these systems, pipe flows are typically established in the horizontal sections of slotted screen completions and inflow control device (ICD) completions; moreover, an annular flow exists in the region between the pipe and the borehole wall. On the basis of the principles of mass and momentum conservation, in the present study, a coupling model considering the variable mass flow of the central tubing, the variable mass flow of the annular tubing and the reservoir seepage is…
  • More
  •   Views:145       Downloads:149        Download PDF
  • Numerical Study of Airborne Droplets Propagation Inside a Hospital Consulting Room
  • Abstract The outbreak of Corona Virus (COVID-19) has spread over a large number of countries. The virus is typically transported inside liquid droplets produced by human beings. As a result, doctors operating in the consulting rooms of hospitals are potentially exposed to high risk. Taking into account the evaporation of droplets and using a hybrid Eulerian-Lagrangian framework to determine the airflow pattern and corresponding motion of droplets, in the present study, the motion of droplets is investigated with regard to the situation in which doctors check patients in front of their bed. A turbulence model (RNG k-ɛ) is used. The purification…
  • More
  •   Views:105       Downloads:95        Download PDF
  • Improving Mechanical Properties of Vitrified Umbilical Arteries with Magnetic Warming
  • Abstract The damage caused by thermal stress during rewarming vitrified biosamples is one of the major obstacles for clinical purposes. Magnetic warming is a highly effective approach to overcome this hurdle and can achieve rapid and spatially homogeneous heating. The current research investigates the effects of magnetic warming on the histological and biomechanical properties of the vitrified umbilical arteries (UAs) through experiments and simulation. The results of experiments show that, for the case of magnetic warming comparing with the conventional water bath, magnetic warming presents better preservation of extracellular matrix (ECM), collagen fibers, elastic fibers, and muscle fibers of the umbilical…
  • More
  •   Views:104       Downloads:90        Download PDF
  • Experimental Study on the Flow Characteristics of a Plate with a Mechanically Choked Orifice
  • Abstract The mechanically choked orifice plate (MCOP) is a new type of device for flow control by which choking conditions for incompressible fluids can be obtained with relatively small pressure losses. Given the lack of relevant results and data in the literature, in the present study, we concentrate on the experimental determination of the flow coefficient for the annular orifice, the pressure distribution in the MCOP, and the characteristics of the choked flow itself. As confirmed by the experimental results, the Reynolds number, the orifice plate thickness, the plug taper, and the eccentricity have an obvious influence on the aforementioned flow…
  • More
  •   Views:111       Downloads:92        Download PDF
  • A Study on the Strength Surplus Coefficient of Cement
  • Abstract This study considers P.O42.5 cement from different sources and evaluates the related surplus coefficient (defined as the proportionality factor linking the measured compressive strength value of the cement after 28 days to the “standard” value of cement strength). The needed tests have been conducted using a mixer, a pressure testing machine, a flexural testing machine, a vibrating table a ramming rod, a feeder and a metal ruler. The average value of the measured cement strength surplus coefficient of cement produced by five distinct cement manufacturers has been found to be 1.16. These results can be used as the basis to…
  • More
  •   Views:118       Downloads:95        Download PDF
Displaying 1-10 on page 1 of 443. Per Page