scholarly journals Numerical Investigation on the Influence of Mechanical Draft Wet-Cooling Towers on the Cooling Performance of Air-Cooled Condenser with Complex Building Environment

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4560 ◽  
Author(s):  
Fan ◽  
Dong ◽  
Xu ◽  
Teng ◽  
Yan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Significant Rise ◽  
Cooling Power ◽  
Air Cooling ◽  
Cooling Towers ◽  
Design Data ◽  
Cooling Performance ◽  
Ambient Wind ◽  
Hot Air ◽  
Complex Building

In air-cooled power units, an air-cooled condenser (ACC) is usually accompanied by mechanical draft wet-cooling towers (MCTs) so as to meet the severe cooling requirements of air-cooling auxiliary apparatuses, such as water ring vacuum pumps. When running, both the ACC and MCTs affected each other through their aerodynamic fields. To make the effect of MCTs on the cooling performance of the ACC more prominent, a three-dimensional (3D) numerical model was established for one 2 × 660 MW air-cooling power plant, with full consideration the ACC, MCTs and adjacent main workshops, which was validated by design data and published test results. By numerical simulation, we obtained the effect of hot air recirculation (HAR) on the cooling performance of the ACC under different working conditions and the effect of MCTs on the cooling performance of the ACC. The results showed that as the ambient wind speed increases, the hot recirculation rate (HRR) of the ACC increased and changed significantly with the change of wind directions. An increase in ambient temperature can cause a significant rise in back pressure of the ACC. The exhaust of the MCTs partially entered the ACC under the influence of ambient wind, and the HRR in the affected cooling units was higher than that of the nearby unaffected cooling units. When the MCTs were turned off, the overall HRR of the ACC decreased. The presence of MCTs had a local influence on the cooling performance of only two cooling units, and then slightly impacted the overall cooling performance of the ACC, which provides a good insight into the arrangement optimization of the ACC and the MCTs.

scholarly journals Evaluation of the Hot Air Recirculation Effect and Relevant Empirical Formulae Applicability for Mechanical Draft Wet Cooling Towers

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3347
Author(s):  
Haotian Dong ◽  
Dawei Wan ◽  
Minghua Liu ◽  
Tiefeng Chen ◽  
Shasha Gao ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Ambient Air ◽  
Calculation Error ◽  
Cooling Towers ◽  
Design Data ◽  
Cooling Performance ◽  
Wind Speeds ◽  
Hot Air ◽  
The Usa

Due to the hot air recirculation, the inlet air enthalpy h1 of mechanical draft wet cooling towers (MCTs) was usually greater than the ambient air enthalpy ha. To realize the cooling performance and accurate design of MCTs, this paper clarified the feasibility of the inlet air enthalpy empirical formula presented by the Cooling Technology Institute (CTI) of the USA. A three-dimensional (3D) numerical model was established for a representative power plant, with full consideration of MCTs and adjacent main workshops, which were validated by design data and published test results. By numerical simulation, the influence of different wind directions and wind speeds on hot air recirculation (HAR) and the influence of HAR on the cooling performance of the MCTs were qualitatively studied based on the concept of hot air recirculation rate (HRR), and the correction value of HRR was compared with the calculated value of the CTI standard. The evaluation coefficient ηh, representing the ratio of the corrected value to the calculated value was introduced to evaluate the applicability of the CTI formula. It was found that HAR was more sensitive to ambient crosswind, and an increase in HRR would deteriorate the tower cooling performance. When the crosswind speed increased from 0 to 15 m/s, ηh, changed from 2.42 to 80.18, and the calculation error increased accordingly. It can be concluded that the CTI empirical HRR formula should be corrected when there are large buildings around the MCTs, especially under high-speed ambient crosswind conditions.

Three-Dimensional Numerical Simulation of the Whole Flow Field on Centrifugal Fan

2012 ◽  
Vol 251 ◽  
pp. 15-20
Author(s):  
Bo Wan ◽  
Xue Fei Liang ◽  
Tao Sun
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Field ◽  
Three Dimensional ◽  
Air Cooling ◽  
Cooling Towers ◽  
Centrifugal Fan ◽  
Axial Fan ◽  
Grain Drying ◽  
Turbo Machinery

Centrifugal fan is a kind of widely used turbo machinery. It is widely used in buildings, mines, factories, tunnels, vehicles, ships and air cooling towers and cooling; grain drying and sending; inflatable hovercraft and propulsion. It has many advantages compared to axial fan. In this paper, we study the numerical simulation of the whole flow field of a High-pressure centrifugal fan called 9-16№15.9D.The researches can contribute to a better design on centrifugal fan.

Film Cooling From Novel Sister Shaped Single-Holes

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Three Dimensional ◽  
Lateral Spreading ◽  
Navier Stokes ◽  
The Novel ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole ◽  
Lift Off

A numerical investigation of the film cooling performance from novel sister shaped single-holes (SSSH) is presented in this paper and the obtained results are compared with a single cylindrical hole, a forward diffused shaped hole, as well as discrete sister holes. Three types of the novel sister shaped single-hole schemes namely downstream, upstream and up/downstream SSSH, are designed based on merging the discrete sister holes to the primary hole in order to reduce the jet lift-off effect and increase the lateral spreading of the coolant on the blade surface as well as a reduction in the amount of coolant in comparison with discrete sister holes. The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The upstream SSSH demonstrates similar film cooling performance to that of the forward diffused shaped hole for the low blowing ratio of 0.5. While it performs more efficiently at M = 1, where the centerline and laterally averaged effectiveness results improved by 70% and 17%, respectively. On the other hand, the downstream and up/downstream SSSH schemes show a considerable improvement in film cooling performance in terms of obtaining higher film cooling effectiveness and less jet lift-off effect as compared with the single cylindrical and forward diffused shaped holes for both blowing ratios of M = 0.5 and 1. For example, the laterally averaged effectiveness for the downstream SSSH configuration shows an improvement of approximately 57% and 110% on average as compared to the forward diffused shaped hole for blowing ratios of 0.5 and 1, respectively.

A CFD-Based Parametric Study on Modification of Discrete Sister Holes Location for the Film Cooling Flow

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Base Case ◽  
Spanwise Direction ◽  
Cooling Performance ◽  
Cooling Flow ◽  
Lift Off ◽  
The Individual

A numerical study on the effects of sister holes locations on film cooling performance is presented. This includes the change of the location of the individual discrete sister holes in the streamwise and spanwise directions, where each one of these directions includes 9 different locations, The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The variation of the sister holes in the streamwise direction provides similar film cooling performance as the base case for both blowing ratios of 0.5 and 1. On the other hand, the spanwise variation of the sister holes’ location has a more prominent effect on the effectiveness. In some cases, as a result of the anti-vortices generated from the sister holes and the repositioning of the sister holes in the spanwise direction, the jet lift-off effect notably decreases and more volume of coolant is distributed in the spanwise direction.

Advanced Cooling Tower Concept for Commercial and Industrial Applications

2014 ◽  
Author(s):  
Sergey Anisimov ◽  
Aleksandr Kozlov ◽  
Paul Glanville ◽  
Mark Khinkis ◽  
Valeriy Maisotsenko ◽  
...  
Keyword(s):  
Cooling Tower ◽  
Industrial Applications ◽  
Process Efficiency ◽  
Limiting Factor ◽  
Cooling Towers ◽  
Water Stream ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler ◽  
The U.S

For the majority of cooling towers installed, of which there are greater than half a million installed in the U.S., tower design uses direct evaporative cooler technology where an ideally enthalpy-neutral process cools the process water stream to a temperature above the ambient wet bulb. This ambient wet bulb temperature is the limiting factor for the process cooling. As such the energy-water connection is clear, these cooling towers are direct consumers of treated water and their cooling performance is intimately tied to the process efficiency.

Thermal Management of Air-Cooling Lithium-Ion Battery Pack

2021 ◽  
Vol 38 (11) ◽  
pp. 118201
Author(s):  
Jianglong Du ◽  
Haolan Tao ◽  
Yuxin Chen ◽  
Xiaodong Yuan ◽  
Cheng Lian ◽  
...  
Keyword(s):  
Lithium Ion Battery ◽  
Thermal Management ◽  
Thermal Performance ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Battery Pack ◽  
Cooling Effect ◽  
Air Cooling ◽  
Safety Issues ◽  
Battery Packs

Lithium-ion battery packs are made by many batteries, and the difficulty in heat transfer can cause many safety issues. It is important to evaluate thermal performance of a battery pack in designing process. Here, a multiscale method combining a pseudo-two-dimensional model of individual battery and three-dimensional computational fluid dynamics is employed to describe heat generation and transfer in a battery pack. The effect of battery arrangement on the thermal performance of battery packs is investigated. We discuss the air-cooling effect of the pack with four battery arrangements which include one square arrangement, one stagger arrangement and two trapezoid arrangements. In addition, the air-cooling strategy is studied by observing temperature distribution of the battery pack. It is found that the square arrangement is the structure with the best air-cooling effect, and the cooling effect is best when the cold air inlet is at the top of the battery pack. We hope that this work can provide theoretical guidance for thermal management of lithium-ion battery packs.

Transferred-Substrate InGaAsP-Based Thermionic Emission Coolers

2000 ◽  
Author(s):  
Christopher J. LaBounty ◽  
Gerry Robinson ◽  
Patrick Abraham ◽  
Ali Shakouri ◽  
John E. Bowers
Keyword(s):  
Thermal Resistance ◽  
Three Dimensional ◽  
Thermionic Emission ◽  
Copper Film ◽  
Cooling Power ◽  
Material System ◽  
Inp Substrate ◽  
Order Of Magnitude ◽  
Thin Copper Film ◽  
Thermally Conducting

Abstract Most optoelectronic devices are based on III-V semiconductors such as the InP/InGaAsP material system. Solid state refrigerators based on the same material system can be monolithically integrated with optoelectronics. Thermionic emission cooling in InGaAsP-based heterostructures has been shown experimentally to provide cooling power densities of several 100 W/cm2. Cooling by several degrees across thin films on the order of a micron thick has been demonstrated. Thermionic emission of hot electrons over heterobarriers allows for enhanced cooling power beyond what is possible from the bulk thermoelectric properties. The thermal resistance of the InP substrate between the hot side of the thin film cooler and the heat sink is found to be a limitation in cooler performance. Several possibilities are examined for replacing the InP substrate with a higher thermally conducting one such as silicon, copper, or even diamond, and a process for substrate transfer to a thin copper film has been developed. Three-dimensional simulations predict an order of magnitude improvement in the thermal resistance of the substrate. Experimental results of packaged InGaAsP coolers with copper substrates will be discussed.

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