Estimating ASME Section III and VIII Heat Exchanger Nozzle Loads

2009 ◽  
Author(s):  
L. Ike Ezekoye ◽  
Colin Arnold
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Power Plant ◽  
Material Properties ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Design Criteria ◽  
Physical Geometry ◽  
External Forces ◽  
Stress Criteria

Heat Exchange Institute (HEI) Standards for Power Plant Heat Exchangers, 4th Edition provides guidance on how to estimate the nozzle loads of cylindrical shells. The procedure covered in one of the appendices of the document relies on WRC Bulletin 107 methodology which uses internal pressure, physical geometry and material properties to estimate external forces and moments. The forces and moments are the limiting loads when the heat exchanger material is taken to yield. The material yield defines the range of possible load combinations that will meet the design criteria. However, for operability, the design criteria sometimes may differ from the yield but usually is based on heat exchanger supplier experience. This paper provides a way to estimate heat exchanger nozzle loads that more closely reflect operating conditions that take into account supplier experience. In this paper, generalized load formulae are developed for the nozzles. The formulae are iteratively solved to meet the stress criteria based on supplier experience. The resultant loads are evaluated using WRC Bulletin 107 to ensure that the loads are bounded by the acceptance criteria. Unbounded loads are rejected and reiterated until the loads are acceptable.

Thermal Analysis Technique for Coolers Operating in Off and Low Load Conditions

2012 ◽  
Author(s):  
Thomas J. Muldoon
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Heat Exchangers ◽  
Cooling Water ◽  
Control Valve ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Inlet Valve ◽  
Plant Personnel ◽  
Load Conditions

The most conservatively designed power plant heat exchangers are designed to meet a maximum heat load with minimum fluid temperature differences. When the input temperatures are less than design maximums, the cooler will usually be in a position of over performance. This relationship is especially true when the heat exchanger is a closed Component Cooling Water (CCW) heat exchanger with inlet fluid at ambient conditions. Maintaining a consistent cooling temperature is an important concern in the operation of a power plant. It is important that the cooling needs of the equipment such as the hydrogen coolers are maintained at a set temperature. Overcooling may not be of benefit to the equipment. The component which cools the service water with the local cooling water is a component cooling water heat exchanger (CCW). The two primary methods of controlling the heat rejection performance on these vessels is to throttling the tubeside flow to get a consistent shell outlet temperature with control valves or leave the tubeside flow constant and by-pass a portion of the shellside flow. Estimating the performance of the heat exchanger with given set of inlet conditions and a fixed design point can be accomplished using a the Number Transfer Units (NTU) method. Opening and closing the control valve is based on the estimated performance. This analysis can be used by power plant personnel to gauge the operation of these vessels over varying operating conditions. The analysis can also include the effect of different values of cleanliness and the extent of throttling. As a unit experiences fouling, additional flow is required to meet the thermal requirements. Depending upon the extent of fouling, the inlet valve will be either opened or closed. Plant personnel may observe the cooling water inlet temperature and the extent to which the inlet valve is open, and use that information to determine possible fouling and setup a maintenance schedule. The following analytical approach for evaluating low, critical, or off load conditions is important in the design and operation of these types of power plant heat exchangers, piping and control valve systems.

Use of Condensing Heat Exchangers in Coal-Fired Power Plants to Recover Flue Gas Moisture and Capture Air Toxics

2013 ◽  
Author(s):  
Edward Levy ◽  
Harun Bilirgen ◽  
Joshua Charles ◽  
Mark Ness
Keyword(s):  
Water Vapor ◽  
Heat Exchanger ◽  
Power Plant ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Power Plants ◽  
Operating Conditions ◽  
Dew Point ◽  
Air Toxics ◽  
Condensing Heat Exchanger

Heat exchangers, which cool boiler flue gas to temperatures below the water vapor dew point, can be used to capture moisture from flue gas and reduce external water consumption for power plant operations. At the same time, thermal energy removed from the flue gas can be used to improve unit heat rate. Recent data also show that emissions of air toxics from flue gas would be reduced by use of condensing heat exchangers. This paper describes results from a slip stream test of a water cooled condensing heat exchanger system at a power plant with a lignite-fired boiler. The flue gas which flowed through the heat exchangers had been extracted from a duct downstream of the electrostatic precipitator. Measurements were made of flue gas and cooling water temperatures, flue gas water vapor concentrations, and concentrations of elemental and oxidized Hg at the inlet and exit of the heat exchanger system. Condensed water was also collected and analyzed for concentrations of H2SO4 and HCl. Results on the effects of the condensing heat exchanger operating conditions on oxidation and capture of Hg and on the capture of sulfuric and hydrochloric acids are described.

Methods to Define Failure Probability for Power Plant Heat Exchangers

2017 ◽  
Author(s):  
Carolyn J. John ◽  
Consuelo E. Guzman-Leong ◽  
Thomas C. Esselman ◽  
Sam L. Harvey
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Fresh Water ◽  
Heat Exchangers ◽  
Power Plants ◽  
Operating Experience ◽  
Operating Conditions ◽  
Microbiologically Influenced Corrosion ◽  
Water Steam ◽  
Over Time

In response to the technical challenges faced by aging plant systems and components at nuclear power plants (NPP), the Electric Power Research Institute (EPRI) has a product entitled Integrated Life Cycle Management (ILCM). The ILCM software is a quantitative tool that supports capital asset and component replacement decision-making at NPPs. ILCM is comprised of models that predict the probability of failure (PoF) over time for various high-value components such as steam generators, turbines, generators, etc. The PoF models allow the user to schedule replacements at the optimum time, thereby reducing unplanned equipment shutdowns and costs. This paper describes a mathematical model that was developed for critical heat exchangers in a power plant. The heat exchanger model calculates the probability of the tubes, shell, or internals failing individually, and then accumulates the failures across the heat exchanger sub-components. The dominant degradation mechanisms addressed by the model include stress corrosion cracking, wear, microbiologically influenced corrosion, flow accelerated corrosion, and particle-induced erosion. The heat exchanger model combines physics-based algorithms and operating experience distributions to predict the cumulative PoF over time. The model is applicable to shell and tube heat exchangers and air-to-water heat exchangers. Many different types of fluids including open cycle fresh water, closed cycle fresh water, sea water, brackish water, air, closed cooling water, steam, oil, primary water, and condensate are included. Examples of PoF over time plots are also provided for different fluid types and operating conditions.

Review of Computer Simulations of Regenerative Heat Exchangers

1978 ◽  
Vol 11 (8) ◽  
pp. 309-312
Author(s):  
A. J. Willmott
Keyword(s):  
Heat Exchanger ◽  
Recent Work ◽  
Computer Simulations ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Design Criteria ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Fuel Savings

Early models of the stationary performance of the regenerative heat exchanger are discussed together with more recent work in which the behaviour under chronologically varying operating conditions is simulated. The need is presented for better control facilities and possibly new design criteria if fuel savings in regenerative heat exchanger non-stationary operations are to be effected.

scholarly journals Investigation of increased corrosion wear of heat exchange equipment pipes

2021 ◽  
Vol 225 ◽  
pp. 06003
Author(s):  
Oleg Kiselev ◽  
Dmitry Polikarpov ◽  
Anna Demidova
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Oil Refining ◽  
Corrosion Wear ◽  
Tube Bundles ◽  
Heat Exchange Equipment

The article discusses the stages of research to determine the possible causes of increased corrosion wear of tube bundles of heat exchangers. The most typical types of damage to heat exchanger pipes are shown, depending on the operating conditions. Recommendations aimed at reducing the corrosion wear of pipe bundles for typical operating conditions at oil refining enterprises.

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

2021 ◽  
Vol 23 ◽  
pp. 42-64
Author(s):  
Boris Basok ◽  
Ihor Bozhko ◽  
Maryna Novitska ◽  
Aleksandr Nedbailo ◽  
Myroslav Tkachenko
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ventilation System ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Operational Parameters ◽  
Cross Sectional ◽  
Distinctive Features ◽  
Sectional Shape ◽  
Experimental Bench

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

Thermo-Mechanical Design of Brazed Plate-Fins Heat Exchanger Based on Finite Element Modeling Using Homogenization Techniques

2009 ◽  
Author(s):  
Johan Dib ◽  
Ivan Lewon ◽  
Boris Martin
Keyword(s):  
Finite Element ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Mechanical Design ◽  
Periodic Structures ◽  
Software Tool ◽  
Design Criteria ◽  
Base Metals ◽  
The Core ◽  
Aluminum Base

Using classical Finite Element (FE) tools to model heat exchangers emphasizes the need to elaborate specific methods to reduce the size of the numerical problem. Among these methods, homogenization techniques can be adapted and used for Brazed Aluminum Plate-Fins Heat Exchangers (BAHX) including layers of periodic structures. Actually the core is formed by stacking single layers consisting of periodic corrugated fins, side-bar and parting sheets which are all made of aluminum base metals, and brazed in a furnace. So in this paper a global methodology of BAHX modeling and design is presented. It integrates homogenization techniques to perform FE calculation and localization techniques to allow applying the appropriate design criteria. Finally, to validate this methodology, results are then compared on a basic heat exchanger modeled both by classical FE tools and a dedicated software tool encapsulating both homogenization and localization techniques.

scholarly journals Analytical and Experimental Investigation of a Plate Fin Heat Exchanger at Cryogenics Temperature

2021 ◽  
Vol 39 (4) ◽  
pp. 1225-1235
Author(s):  
Ajay K. Gupta ◽  
Manoj Kumar ◽  
Ranjit K. Sahoo ◽  
Sunil K. Sarangi
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Cryogenic Temperature ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Compact Size

Plate-fin heat exchangers provide a broad range of applications in many cryogenic industries for liquefaction and separation of gasses because of their excellent technical advantages such as high effectiveness, compact size, etc. Correlations are available for the design of a plate-fin heat exchanger, but experimental investigations are few at cryogenic temperature. In the present study, a cryogenic heat exchanger test setup has been designed and fabricated to investigate the performance of plate-fin heat exchanger at cryogenic temperature. Major parameters (Colburn factor, Friction factor, etc.) that affect the performance of plate-fin heat exchangers are provided concisely. The effect of mass flow rate and inlet temperature on the effectiveness and pressure drop of the heat exchanger are investigated. It is observed that with an increase in mass flow rate effectiveness and pressure drop increases. The present setup emphasis the systematic procedure to perform the experiment based on cryogenic operating conditions and represent its uncertainties level.

scholarly journals Experimental Study for Counter to Cross Flow Air-cooled Heat Exchangerof Annular Tube having Internal Circular grooving at Different pitches - A Review

2020 ◽  
pp. 268-274
Author(s):  
Suneel Nagar ◽  
Ajay Singh ◽  
Deepak Patel
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Operating Conditions ◽  
Theory And Practice ◽  
Thermal Flow ◽  
Total Cost ◽  
Literature Theory ◽  
Modern Analytical ◽  
Annular Tube

The objective of this study is to provide modern analytical and empirical tools for evaluation of the thermal-flow performance or design of air-cooled heat exchangers (ACHE) and cooling towers. This review consist various factors which effect the performance of ACHE. We introduced systematically to the literature, theory, and practice relevant to the performance evaluation and design of industrial cooling. Its provide better understanding of the performance characteristics of a heat exchanger, effectiveness can be improved in different operating conditions .The total cost of cycle can be reduced by increasing the effectiveness of heat exchanger.

The Effect of Geometrical Features on Air-Side Heat Transfer and Friction Characteristics, and Optimization of a Large-Size Plain Fin-and-Tube Heat Exchanger by 3-D Numerical Simulation

2009 ◽  
Author(s):  
M. Izadi ◽  
D. K. Aidun ◽  
P. Marzocca ◽  
H. Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Simple Algorithm ◽  
Operating Conditions ◽  
Friction Characteristics ◽  
Tube Heat Exchanger ◽  
Large Size ◽  
Geometrical Features

The effect of geometrical features on the air-side heat transfer and friction characteristics of an industrial plain fin-and-tube heat exchanger is investigated by 3-D numerical modeling and simulations. The heat exchanger has been designed and employed as an intercooler in a gas power plant and is a large-size compact heat exchanger. Most of the available design correlations developed so far for plain fin–and–tube heat exchangers have been prepared for small-size exchangers and none of them fits completely to the current heat exchanger regarding the geometrical limitations of correlations. It is shown that neglecting these limitations and applying improper correlations may generate considerable amount of error in the design of such a large-size heat exchanger. The geometry required for numerical modeling is produced by Gambit® software and the boundary conditions are defined regarding the real operating conditions. Then, three-dimensional simulations based on the SIMPLE algorithm in laminar flow regime are performed by FLUENT™ code. The effect of fin pitch, tube pitch, and tube diameter on the thermo-hydraulic behavior of the heat exchanger is studied. Some variations in the design of the heat exchanger are suggested for optimization purposes. It is finally concluded that the current numerical model is a powerful tool to design and optimize of large-size plain fin-and-tube heat exchangers with acceptable accuracy.

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