scholarly journals An analytical model on thermal performance evaluation of counter flow wet cooling tower

2017 ◽  
Vol 21 (6 Part A) ◽  
pp. 2491-2501 ◽  
Author(s):  
Qian Wang ◽  
Pei-Hong Wang ◽  
Zhi-Gang Su
Keyword(s):  
Analytical Model ◽  
Thermal Performance ◽  
Power Plants ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Counter Flow ◽  
Water Surface Temperature ◽  
Mass Transfer Processes ◽  
Proposed Model ◽  
Simultaneous Heat

This paper proposes an analytical model for simultaneous heat and mass transfer processes in a counter flow wet cooling tower, with the assumption that the enthalpy of the saturated air is a linear function of the water surface temperature. The performance of the proposed analytical model is validated in some typical cases. The validation reveals that, when cooling range is in a certain interval, the proposed model is not only comparable with the accurate model, but also can reduce computational complexity. In addition, with the proposed analytical model, the thermal performance of the counter flow wet cooling towers in power plants is calculated. The results show that the proposed analytical model can be applied to evaluate and predict the thermal performance of counter flow wet cooling towers.

scholarly journals On Thermal Performance of Seawater Cooling Towers

2010 ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Governing Equations ◽  
Detailed Model ◽  
Salt Deposition ◽  
Transfer Processes ◽  
Mass Transfer Processes

Seawater cooling towers have been used since the 1970’s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems including salt deposition, packing blockage, corrosion, and certain environmental impacts from salt drift and blowdown return. In addition, the salinity of seawater affects the thermophysical properties which govern the thermal performance of cooling towers, including vapor pressure, density, specific heat, viscosity, thermal conductivity and surface tension. In this paper, the thermal performance of seawater cooling towers is investigated using a detailed model of a counterflow wet cooling tower. The model takes into consideration the coupled heat and mass transfer processes and does not make any of the conventional Merkel approximations. In addition, the model incorporates the most up-to-date seawater properties in the literature. The model governing equations are solved numerically and its validity is checked by data in the literature. Based on the results of the model, a correction factor is obtained which characterizes the degradation of the cooling tower effectiveness when seawater is used.

Computer Simulation of Transport Phenomena in Evaporative Cooling Towers

1988 ◽  
Vol 110 (2) ◽  
pp. 190-196 ◽  
Author(s):  
D. J. Benton ◽  
W. R. Waldrop
Keyword(s):  
Power Plants ◽  
Field Data ◽  
Cooling Tower ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Governing Equations ◽  
Cooling Process ◽  
Transfer Processes ◽  
Finite Integral ◽  
Simultaneous Heat

A computer model of the simultaneous heat, mass, and momentum transfer processes occurring throughout an entire cooling tower is described in this paper. The model includes the flexibility to analyze the several configurations, fill arrangements, and flow distributions commonly used by the power industry. The fundamental governing equations are solved using a finite-integral technique to provide a quasi-two-dimensional description of the flow and cooling process within the tower. The model has been successfully compared with field data from cooling towers at three TVA power plants as well as data from other utilities. Each of these towers was significantly different in design, thereby demonstrating the versatility of the model for correctly predicting the cooling performance of mechanical and natural draft towers, as well as crossflow and counterflow orientations, for a range of meteorological and plant operating conditions.

scholarly journals On Thermal Performance of Seawater Cooling Towers

2010 ◽  
Vol 133 (4) ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Governing Equations ◽  
Detailed Model ◽  
Salt Deposition ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Seawater Salinity

Seawater cooling towers have been used since the 1970s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems, including salt deposition, packing blockage, corrosion, and certain environmental impacts from salt drift and blowdown return. In addition, the salinity of seawater affects the thermophysical properties that govern the thermal performance of cooling towers, including vapor pressure, density, specific heat, viscosity, thermal conductivity, and surface tension. In this paper, the thermal performance of seawater cooling towers is investigated using a detailed model of a counterflow wet cooling tower. The model takes into consideration the coupled heat and mass transfer processes and does not make any of the conventional Merkel approximations. In addition, the model incorporates the most up-to-date seawater properties in the literature. The model governing equations are solved numerically, and its validity is checked against the available data in the literature. Based on the results of the model, a correction factor that characterizes the degradation of the cooling tower effectiveness as a function of seawater salinity and temperature approach is presented for performance evaluation purposes.

An Analytical Approach to the Heat and Mass Transfer Processes in Counterflow Cooling Towers

2006 ◽  
Vol 128 (11) ◽  
pp. 1142-1148 ◽  
Author(s):  
Chengqin Ren
Keyword(s):  
Mass Transfer ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Analytical Model ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Accurate Analysis ◽  
Transfer Resistance ◽  
Transfer Processes ◽  
Mass Transfer Processes

Quick and accurate analysis of cooling tower performance, outlet conditions of moist air, and parameter profiles along the tower height is very important in rating and design calculations. This paper developed an analytical model for the coupled heat and mass transfer processes in counterflow cooling towers based on operating conditions more realistic than most conventionally adopted Merkel approximations. In modeling, values of the Lewis factor were not necessarily specified as unity. Effects of water loss by evaporation and water film heat transfer resistance were also considered in the model equations. Within a relatively narrow range of operating conditions, the humidity ratio of air in equilibrium with the water surface was assumed to be a linear function of the surface temperature. The differential equations were rearranged and an analytical solution was developed for newly defined parameters. The analytical model predicts the tower performances, outlet conditions, and parameter profiles quickly and accurately when comparing with the numerical integration of the original differential equations.

scholarly journals Experimental Study on Effect of Water Spray Characteristics on Performance of Cooling Tower

2020 ◽  
Vol 170 ◽  
pp. 01009
Author(s):  
Akshay S. Dhurandhar ◽  
Amarsingh B. Kanase-Patil
Keyword(s):  
Power Plants ◽  
Cooling Tower ◽  
Thermal Power ◽  
Evaporative Cooling ◽  
Hot Water ◽  
Spray Angle ◽  
Counter Flow ◽  
Steam Power ◽  
To Come ◽  
Spiral Type

Cooling tower is an indispensable part, used as a direct contact type heat exchanger mainly for evaporative cooling. Cooling tower generally dissipates, remove heat from thermal power plants. In an induced draft cooling tower of counter flow, used for a mini-steam power plant, hot water enters at the top, while the air is introduced at the bottom and exits at the top, air is allowed to come in contact with falling water droplets, causing evaporative cooling. A possibility of desired change with different spray angle, patterns, is tried and analysed. On findings, best suited spray nozzle angle resulted is 90°, and amongst three spray patterns, full cone, hollow cone and spiral type nozzle; full cone nozzle of 90° spray angle helps achieving efficiency up to 82%. The range increases successively from 9.8°C to 15.5°C for FC nozzle, in approach to WBT; the desirable fall of 3.56°C is attained with effectiveness of 81.63%.

Effect of Wind Directions on the Thermal Performance of Three Aligned NDDCT: Parallel and Perpendicular Directions

2012 ◽  
Vol 232 ◽  
pp. 218-222
Author(s):  
Samad Ghafarigousheh ◽  
Ali Akbar Golneshan
Keyword(s):  
Numerical Model ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Flow Parameters ◽  
Pressure Fields ◽  
Connection Line

In this paper a 3-D numerical model is used to investigate the thermal performance of a three aligned unit of NDDCT under crosswind condition. The computed results show that, there are major differences in computed velocity patterns and pressure fields around the cooling tower due to neighboring of a number of cooling towers will result considerable changes in computed flow parameters hence; the thermal performance losses for the single tower under crosswind are superior to those when this towers are incorporated in aligned arrangement. Results also show that the best thermal performance of the three aligned NDDCT is achieved when the crosswind is directed along the towers connection line.

scholarly journals Thermal Performance Evaluation of Seawater Cooling Towers

2011 ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
Iqbal S. Husain ◽  
Syed M. Zubair ◽  
John H. Lienhard
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fresh Water ◽  
Thermal Performance ◽  
Operating Conditions ◽  
Thermal Design ◽  
Cooling Towers ◽  
Detailed Model ◽  
Transfer Processes ◽  
Mass Transfer Processes

Seawater has been used for long time as a cooling fluid in heat exchangers to reduce fresh water usage in industry and power plants. The thermophysical properties of seawater are different from those of fresh water due to the salt content or salinity. This difference is sufficient to affect the heat and mass transfer processes which in turn change the thermal performance. Thermal design of fresh water cooling towers is described in detail in many textbooks and handbooks. However, only a rule of thumb is frequently used for designing of seawater cooling towers. This rule recommends degrading the tower performance by approximately 1% for every 10,000 ppm of salts in the feed water. In this paper, the thermal performance of seawater cooling towers is presented using a detailed model of counterflow wet cooling towers which takes into consideration the coupled simultaneous heat and mass transfer processes and uses state-of-the-art seawater properties from the literature. The model governing equations are solved numerically and the validity of this model is checked using new experimental data that has been measured using a bench top counterflow seawater cooling tower. The effect of the variation of seawater salinity as well as other operating conditions on the effectiveness and Merkel number is investigated.

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