Steel Tube Bundle Research Articles

A Study on the Development of the Stainless Steel Tube Bundle Structure Detecting System Using Ultrasonic Guided Wave.

In this study, an ultrasonic guided wave system that can be used to detect broken tubes in stainless steel tube bundle structures (e.g., heat exchangers) with fairly narrow spacing between the tubes was designed. The interval between the tubes was 1.5 mm, and the thickness of the strip with a transducer that can be inspected by passing between the tubes was designed to be 1 mm. The damaged specimen was filled with water, and it was confirmed that the signal amplitude was smaller than that of the normal specimen filled with air. The ultrasonic properties of stainless steel were analyzed using the developed system, and it is expected that this will contribute to breakage inspection for tube bundles with narrow spacing.

Study on fatigue performance of double cover plate through-core bolted joint of rectangular concrete-filled steel tube bundle wind turbine towers

Rectangular steel tube concrete bundle wind turbine towers is a new type of tower structure with high prefabrication, convenient installation, convenient transportation and good integrity.Based on the uniaxial tensile test and fatigue loading test of the double cover plate through-core bolted joint, the stress condition of the key connection parts of the structure is analyzed, the S-N curve of the joint under parameter expansion is summarized, and the Weibull distribution test is carried out for the fatigue life of the concrete inside the joint. Finally, the fatigue damage of the joint are analyzed. The results show that the failure mode of the double cover plate through-core bolted joint under fatigue loading is bolt shear; Through S-N curve fitting, the S-N curve expression and fatigue limit value of different types of joints are obtained. It is found that under the shear failure mode, the fatigue limit of different types of joints is higher than the limit value specified in GB50017–2017, EC3 and AISC-360; The fatigue life of concrete at different loading factors conforms to the two parameter Weibull distribution.The damage analysis of the joint through the high cycle fatigue damage model shows that the trend of a sharp increase in the damage rate of the joints in the late loading period can better explain the phenomenon of instantaneous fracture. The research results of this paper can provide reference for the analysis, research and application of wind turbine towers.

PREDICTION SULPHURIC ACID AND WATER VAPOUR DEW POINT TEMPERATURES OF FLUE GASES AND COMBUSTION ANALYSIS FOR SOLID FUELS IN TURKEY

In the study, the combustion analysis is examined for the solid fuels in Turkey. The principal aim of the analysis is determined the limits and obstacles in the design heat exchanger to avoid the corrosion risk on the heat exchanger surfaces in the latent heat recovery applications from waste flue gas. To do this, in which regions of the heat exchanger the flue gas temperature reached to the sulphuric acid and water vapour dew point temperatures are required to predict. In order to predict the condensing zone, an air preheater for the coal-fired boiler in a heating system is designed using finite difference method. Designed the air preheater is consists of the counter-cross flow, Ushaped stainless steel tube bundle. The tube is discredited 200 cells to one-dimensional during the flow. The heat transfer rates, the flue gas and air inlet and outlet temperatures, surface temperatures of the tube wall, the mole fractions of water and sulphuric acid vapour, the other non-condensing gases in the flue gas are calculated in each discrete cell. According to the results of the study, while the dew point temperature of the water vapour changes over the range 30-40 °C, the acid dew point temperature waves to 125 °C from 140 °C for the coal types mined in Turkey.

Study on Mechanical Properties of Self-Compacting Concrete and Its Filled in-Line Multi-Cavity Steel Tube Bundle Shear Wall

In this paper, five groups of C40 fly ash and silica fume self-compacting concrete (SCC) mix proportion tests and in-line multi-cavity steel tube bundle self-compacting concrete shear wall axial compression performance tests and numerical simulation are completed and presented. The influence of fly ash and silica fume additions on SCC mechanical properties and the filled in-line multi-cavity steel tube bundle shear wall mechanical properties are analyzed and studied. With an increase in the fly ash content from 10% to 40%, the compressive strength of self-compacting concrete increases firstly and then decreases. When the fly ash content is 30% and the silica fume content is 4%, the compressive strength of the 28 d age self-compacting concrete is the highest and the compressive strength formula of the wrapped curing SCC is proposed. The failure of steel tube bundle is multi-wave buckling failure. As the SCC is most obviously affected by the collar at the corner point of the steel tube bundle, its compressive strength is 110 MPa, and is 96 MPa higher than the concrete at the middle point of the web. The deformation resistance of SCC is obviously enhanced by the confinement effect.

Finite Element Analysis and Calculation of Normal Section Bearing Capacity of Steel Tube Bundle Composite Shear Wall

Finite Element Analysis and Calculation of Normal Section Bearing Capacity of Steel Tube Bundle Composite Shear Wall

Nanoporous membrane tube condensing heat transfer enhancement study

A Transport Membrane Condenser (TMC), made from nanoporous membrane tube bundles, was developed to recover the water vapor and its significant amount of latent heat from boiler flue gases to improve boiler efficiency and save water. Experiments have been carried out to study the phenomena for both a nanoporous membrane tube bundle and an impermeable stainless steel tube bundle with the same characteristic dimensions. Flue gas streams with water vapor mass fraction 11.3%, temperature range from 65°C to 95°C are used for the experimental study, which covers the typical TMC waste heat recovery application parameter ranges. Results show convection Nusselt numbers of the membrane tube bundle are 50–80% higher than that of the impermeable stainless steel tube bundle at typical condensation heat transfer conditions. The parametric study has been done by varying cooling water inlet flow rate, water inlet temperature, flue gas inlet flow rate, inlet temperature, and inlet dew point. The condensing heat transfer enhancement effect gives a good perspective for using nanoporous membrane surface to design high efficiency condensing heat exchangers to recover both water vapor and its latent heat from high moisture content low grade waste heat streams.

Experimental study of condensation heat transfer characteristics of horizontal tube bundles in vacuum states

To develop an excellent heat transfer element under the vacuum condition, experiments about the heat transfer performance of horizontal tube bundles of different materials under various vacuum conditions were carried out, including the stainless steel tube, the brass tube, the Ni-based implanted steel tube and the ion implanted brass tube. The relative trends show that the condensation heat transfer coefficient and the overall heat transfer coefficient of bundles of four materials all increase with the vacuum degree, especially, those of the Ni-based implanted steel tube and the ion implanted brass tube. Under a high vacuum condition (0.07 MPa), the condensation heat transfer coefficient of the Ni-based implanted steel tube bundle is about 1.4 times of that of the stainless steel tube bundle, the condensation heat transfer coefficient of the ion implanted brass tube bundle is found to be about 1.3 times of that of the common brass tube bundle. Therefore, according to the condensation heat transfer characteristics studied under high vacuum conditions, it is believed that a dropwise condensation is partly achieved on the surface of these two implanted tube bundles, and the ion implantation is shown to be an effective method to achieve the dropwise condensation. Based on this study, it is believed that the Ni-based steel tube may replace the brass tube, which is more expensive as a heat transfer component.

Experimental Research on Heat Transfer Characteristics of Tube Bundles of Different Materials under Vacuum Conditions

In order to find an excellent kind of heat transfer element under vacuum condition, the heat transfer performance of tube bundles of different materials in vacuum state was studied through experiments, of which include stainless steel tube, brass tube, Ni-based implanted steel tube and ion implanted brass tube. The relative curves prove that the condensation heat transfer coefficient and the overall heat transfer coefficient of four kinds of bundles all increase with the rising vacuum and increasing Re value, especially of the Ni-based implanted steel tube and the ion implanted brass tube. Under higher vacuum (0.07MPa), for larger Re value (24613), it was found that the condensation heat transfer coefficient of Ni-based implanted steel tube bundle is about 3 times that of the stainless steel tube bundle, the condensation heat transfer coefficient of ion implanted brass tube bundle is about 2.4 times that of the common brass tube bundle as well. Therefore, it is believed that partly dropwise condensation was achieved on the surface of these two implanted tube bundles, and ion implantation is proved to be an effective method of dropwise condensation attainment. According to the conclusion, it is considered that the Ni-based steel tube can substitute more expensive brass tube as heat transfer component to some extent.

Failure analysis of welded 0Cr13Al tube bundle in a heat exchanger

The cracking of 0Cr13Al stainless steel tube bundle in condensate/heavy gas oil (HGO) heat exchanger in a petrochemical plant was studied to investigate the failure mechanism. The chemical composition, elements distribution and the morphology of the cracks were analyzed. The results showed that intergranular stress corrosion cracking (ISCC) was the main reason for this failure, and welding microfissures promoted the failure. Strict welding processes, and materials that are not susceptible to intergranular cracking, such as TP321 stainless steel, are suggested to avoid such failures in future application.

STUDIES ON EQUIPMENT CORROSION IN CATALYTIC REFORMATION OF C1 - C5 FRACTION

Observations and data regarding the intense corrosion and deposit phenomena of the carbon steel tube bundle of the heat exchanger are presented. The bundle ensures the cooling of the light fraction C1 - C5 from the top of the distillation column which carries out the removal of pentane and smaller derivates into the RC equipment. Chemical and mineralogical analyses confirm the aggressive action of the fluids flowing through the exchanger. Tests have been done in order to replace the carbon steel with austenitic stainless steel into the manufacturing process of the tube bundle. The corrosion behaviour of the selected metallic materials in recycled cooling water and technological fluids was monitored.

Estimation of gas holdup in a slurry bubble column with internals: nitrogen-Therminol-magnetite system

Nitrogen gas holdup is measured in a bubble column, 0.305 m in internal diameter, as a function of temperature(296–473 K), gas velocity (1.5 to 111 mm s −1), and solids concentration (0 to 40 wt.%) for nitrogen-Therminol-magnetite system. The column is equipped with a thirty-seven 19 mm outer diameter stainless steel tube bundle, tubes being arranged in an equilateral configuration with a pitch of 36.5 mm. The qualitative variations of gas holdup with operating parameters are discussed in the light of bubble dynamics and foaming characteristics. Several commonly employed correlations are found inadequate to reproduce the gas holdup data quantitatively. A simpler approach based on the drift-flux theory could correlate the data with one adjustable parameter which is physically identified as the rise velocity of a single bubble in an infinite medium.

A vacuum technic for the chemist

A Transport Membrane Condenser (TMC), made from nanoporous membrane tube bundles, was developed to recover the water vapor and its significant amount of latent heat from boiler flue gases to improve boiler efficiency and save water. Experiments have been carried out to study the phenomena for both a nanoporous membrane tube bundle and an impermeable stainless steel tube bundle with the same characteristic dimensions. Flue gas streams with water vapor mass fraction 11.3%, temperature range from 65 °C to 95 °C are used for the experimental study, which covers the typical TMC waste heat recovery application parameter ranges. Results show convection Nusselt numbers of the membrane tube bundle are 50–80% higher than that of the impermeable stainless steel tube bundle at typical condensation heat transfer conditions. The parametric study has been done by varying cooling water inlet flow rate, water inlet temperature, flue gas inlet flow rate, inlet temperature, and inlet dew point. The condensing heat transfer enhancement effect gives a good perspective for using nanoporous membrane surface to design high efficiency condensing heat exchangers to recover both water vapor and its latent heat from high moisture content low grade waste heat streams.