Experimental Studies of Tube Frettings in Steam Generators and Heat Exchangers

1979 ◽  
Vol 101 (2) ◽  
pp. 125-133 ◽  
Author(s):  
P. L. Ko
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
Room Temperature ◽  
Operating Temperature ◽  
Experimental Studies ◽  
Steam Generators ◽  
Standard Equipment ◽  
Flow Rates ◽  
Support Interaction ◽  
Design Life

High flow rates in steam generators and heat exchangers may create flow-induced tube vibrations which cause local wear through impacting and rubbing on tube supports and/or with adjacent tubes. The steam generators in CANDU power plants have a design life of 30 yr; it is, therefore, essential that design criteria be developed to minimize tube fretting and to establish acceptable limits of vibration. Standard equipment has been developed to study the effect on tube fretting due to various parameters, such as tube/tube-support interaction, materials combinations, and support geometry. Tests have been conducted in water and steam at boiler operating temperature (265°C) and at room temperature.

scholarly journals PENGARUH DEBIT TERHADAP UNJUK KERJA ALAT PENUKAR KALOR DAN PENURUNAN SUHU RUANGAN

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Mirmanto Mirmanto ◽  
I Made Adi Sayoga ◽  
Zulkarnain Zulkarnain
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Room Temperature ◽  
Rapid Development ◽  
Volumetric Flow Rate ◽  
Working Fluid ◽  
Flow Rates ◽  
Pressure Drops ◽  
Growth Industry ◽  
Pipe Heat

ABSTRACTDue to population growth, industry advance and rapid development, fresh and comfortable air may be difficult to get. Conditioning the air to get comfort environment may be a basic demand for people, but the prices of the device and its operation for this purpose are expensive. This research tries to solve this problem but it is just only to know the capability of the heat exchanger  to transfer/ absorb heat and is not to cool the room to be below the ambient temperature. The working fluid used was clean water and the heat exchangers employed were parallel and serpentine which were made of copper pipes with a diameter of 1/4 inch and 1/2 inch (for the header). The volumetric flow rates used were 300 ml/minutes, 400 ml/minutes and 500 ml/minutes. While the heat that should be absorbed by the water from the room is 50 W, 100 W and 150 W. The results show that the effect of volumetric flow rate on heat exchanger performance and room temperature is insignificant. From the pressure drop results, the parallel pipe heat exchanger has lower pressure drops while the serpentine has higher pressure drops. 

Wear Studies of Materials for Tubes and Antivibration Bars in Nuclear Steam Generators

1996 ◽  
Vol 118 (3) ◽  
pp. 287-300 ◽  
Author(s):  
P. L. Ko ◽  
M.-C. Taponat ◽  
M. Zbinden
Keyword(s):  
Relative Motion ◽  
Nuclear Power ◽  
Room Temperature ◽  
High Flow ◽  
Steam Generators ◽  
Wear Model ◽  
Flow Rates ◽  
Wear Rates ◽  
Inconel 600 ◽  
Wear Damage

Wear occurs as a result of relative motion at the interface of two contacting bodies. In nuclear power steam generators, high flow rates can induce vibration of the tubes resulting in wear damage due to impact and sliding contacts between the tubes and their supports. A research project aiming to gain better understanding of the mechanisms and mechanics involved in vibratory wear and to develop a more versatile predictive wear model was carried out. Combinations of Inconel tubes against flat antivibration bars of 403 SS and electrolytic-chrome plated Inconel 600 were tested under conditions of reciprocating sliding and impacting in water at room temperature and at 250°C. The results show that, depending on the material combinations and he loading conditions, distinctively different wear mechanisms and often drastically different wear rates can occur.

The Fluid Elastic Instability of Concentric Arrays of Tube Bundles Subjected on Cross Flow

2018 ◽  
Author(s):  
Liyan Liu ◽  
Wei Xu ◽  
Kai Guo ◽  
Zhanbin Jia ◽  
Yang Wang ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
High Speed ◽  
Nuclear Power ◽  
Power Plants ◽  
Tube Bundle ◽  
Experimental Studies ◽  
Cross Flow ◽  
High Speed Photography ◽  
Elastic Instability ◽  
Tube Bundles

Concentric arrays of tube bundles are applied extensively in heat exchangers at nuclear power plants. Flow induced vibration is one of the main causes of heat exchanger failures. However, there is no corresponding standard and basic parameters in the design code of different countries for concentric arrays of tube bundles. The fluid elastic instability of this type of heat exchangers cannot be calculated, and the design criteria is lacked. In this paper, a circulating water tunnel experimental facility were set up to test the vibration characteristic of concentric arrays subjected to cross flow. A non-contact measurement method based on high-speed photography imaging technology were adopted, which improved the accuracy of the test. Three kinds of tube bundles (0-degree angle, 15-degree angle and 30-degree angle arrangement, radial/circumferential pitch being 33.6/36.4 mm) were studied. The vibration frequency, amplitude and critical velocity of the tube bundle were investigated by changing the flow velocity. Computational fluid dynamics and fluid-structure interaction method were applied to simulate the fluid elastic instability of tube bundles, that were further verified by the experiments. Meanwhile, the numerical simulation supplements the contents of the experimental studies, which is utilizable to investigate and research the fluid elastic instability. The results of this work could provide references for the design of concentric array heat exchangers.

Design Principles and Sizing Approach of Unfired Once-Through Steam Generators

2011 ◽  
Author(s):  
E. Hamid ◽  
M. Newby ◽  
P. Pilidis
Keyword(s):  
Heat Transfer ◽  
Power Systems ◽  
Heat Recovery ◽  
Power Plants ◽  
Design Principle ◽  
New Technology ◽  
Combined Cycle ◽  
Steam Generators ◽  
Scaled Model ◽  
Flow Rates

One of the key elements of increasing the thermal efficiency of a combined cycle power plant (CCPP) is to improve the design and operation of the heat recovery steam generators (HRSG) utilized in the cycle. Once-through steam generator (OTSG) is a new technology introduced for heat recovery in power systems. It eliminates boiler drums and other components of conventional HRSGs. The simplicity and compactness of an OTSG justifies its application in combined cycle power plants. This paper describes a design principle and an analytical sizing approach that will assist OTSG’s designers to achieve a good design by determining the core dimension, volume of an OTSG for given flow rates and their entering and leaving temperatures as well as the heat transfer area on the smoke side. The developed model has been tested with reference to a scaled model of an existing OTSG that is installed at Manx Electricity Authority and the results were promising. The overall characteristics of heat transfer and pressure drop distributions of the OTSG “scaled model” shows general agreement with the real characteristics of the existing OTSG with error values less than 1%.

Acoustical Resonance of Tube-in-Shell Units

1996 ◽  
Vol 118 (3) ◽  
pp. 299-305 ◽  
Author(s):  
C. Smoglie
Keyword(s):  
Heat Exchangers ◽  
Theoretical Basis ◽  
Reasonable Agreement ◽  
Power Plants ◽  
Cross Flow ◽  
Relative Magnitude ◽  
Noise Emission ◽  
Steam Generators ◽  
Tube Arrays ◽  
Moisture Separator

Severe noise emission due to acoustical resonance can occur in conduits or chambers containing large tube arrays subjected to fluid cross flow, as is the case in many heat exchangers and steam generators. A theoretical basis obtained from updated literature is used to assess excitation and damping forces. Whether acoustical resonance is to be expected or not depends upon the relative magnitude of both forces. A calculation method is proposed for the prediction of acoustical resonance and its frequency. The method has been checked by using geometrical and experimental data for Moisture Separator Reheaters of two different power plants. Results show reasonable agreement between predictions and measurements. Two methods are suggested for the suppression of existing resonance.

АКУСТИЧНА ПОМІТНІСТЬ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ З СИЛОВИМИ УСТАНОВКАМИ НА БАЗІ ПОРШНЕВИХ ДВИГУНІВ

2020 ◽  
pp. 62-80
Author(s):  
В. В. Руденко ◽  
И. В. Калужинов ◽  
Н. А. Андрущенко
Keyword(s):  
Control System ◽  
Internal Combustion Engine ◽  
Power Plants ◽  
Combustion Engine ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Internal Combustion ◽  
Detection Range ◽  
Acoustic Signature ◽  
Static Conditions

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of noise reduction from UAVs urgent both from the point of view of acoustic imperceptibility and ecology.The aim of the work is to determine a set of methods that help to reduce the visibility of UAVs in the acoustic range. It is shown that the main source of noise from the UAV on the ground is the power plant, which includes the engine and the propeller. The parameters of the power plants influencing the processes that determine the acoustic signature of the UAV were investigated. A comprehensive analysis of the factors affecting visibility was carried out. The power plants include two-stroke and four-stroke engines, internal combustion and two-blade propellers. The use of silencers on the exhaust of the internal combustion engine was considered. The spectral characteristics of the acoustic fields of the propeller-driven power plants for the operating sample of the UAV "Eco" were obtained. The measurements were carried out in one-third octave and 1/48 octave frequency bands under static conditions. The venue is the KhAI airfield. Note that the propellers that were part of the power plants operated at Reynolds numbers (Re0,75<2*105), which can significantly affect its aerodynamic and acoustic characteristics. It is shown that when choosing a UAV control system, one should take into account the fact that two-stroke piston engines are the dominant source in the noise of propeller-driven control systems in the absence of a hood and mufflers in the intake and exhaust tracts. The use of a four-stroke internal combustion engine significantly reduces the noise of the control system. In the general case, the position of the boundaries of the zone of acoustic visibility of a UAV at the location of the observer is determined by the ratio between the intensity of acoustic radiation perceived by the observer from the UAV and the intensity of sound corresponding to the natural acoustic background and depends on the degree of manifestation of acoustic effects accompanying the propagation of sound in a turbulent atmosphere - the refraction of sound waves. Absorption and dissipation of acoustic energy. The calculation and comparison of the UAV detection range was carried out taking into account the existing natural maskers.The results of experimental studies are presented that allow assessing the degree of acoustic signature of the UAV. A set of measures aimed at reducing the intensity of the acoustic signature of the UAV in various regions of the radiation spectrum has been determined.

ALLEGHENY LUDLUM AL 29-4C

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Exchangers ◽  
Power Plants ◽  
High Strength ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Corrosion Resistant Alloy ◽  
Geothermal Power

Abstract AL 29-4C is a highly corrosion resistant alloy with a relatively high strength. This combination allows the use of lighter gage tubes, and has led to its use in the brine heat exchangers of geothermal power plants. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-554. Producer or source: Allegheny Ludlum Corporation.

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

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