Dynamic Analysis of End Conditions for Shell Side Pipings of STHE

2019 ◽  
Author(s):  
Nitin D. Pagar ◽  
S. H. Gawande
Keyword(s):  
Heat Exchangers ◽  
Vibration Analysis ◽  
Power Plants ◽  
Vital Role ◽  
Fretting Wear ◽  
Shell Side ◽  
Process Industries ◽  
End Conditions ◽  
Energy Conversion Systems ◽  
Shell And Tube

Abstract Shell and tube heat exchangers [STHE] play a very vital role in energy conversion systems, process industries like chemical, pharmaceutical, refineries etc. and in different power plants. For designing shell and tube heat exchangers, the tubes vibrational response (internally) to any random excitations of fluid flow need to be understandable. Also, circumferential inlet pipe or tube at the entrance region of the shell side, generally subject to the fluid thrust in the bends of typical pipe arrangements. It produces loadings forces and moments, leading to unavoidable vibrations. The goal of vibration analysis is to ensure that fatigue damage or fretting wear does not occur, as well as, predicted frequencies, amplitudes shall be within acceptable limits criteria. This paper reports the vibration analysis of different piping arrangement of different end conditions to understand its effects on frequencies and modes so that a designer must mitigate it, at the initial stage. Axial, lateral and torsional vibrations are analyzed for different end conditions. The boundary conditions used are both ends fixed, one end fixed and other end free, both ends free and one end fixed-other end attached to a weight. Analytical procedure is carried out to determine the frequencies for axial, lateral and torsional cases. FEA analysis and experiment using an FFT analyzer is carried out to check the convergence of the results. Very useful results are established which generates the philosophy to protect the pipings from the resonant frequencies subjected to different end conditions.

The Effect of Baffles in Shell and Tube Heat Exchangers

2009 ◽  
Vol 62-64 ◽  
pp. 694-699 ◽  
Author(s):  
E. Akpabio ◽  
I.O. Oboh ◽  
E.O. Aluyor
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Proper Position ◽  
Process Industries ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Optimal Values ◽  
Side Flow

Shell and tube heat exchangers in their various construction modifications are probably the most widespread and commonly used basic heat exchanger configuration in the process industries. There are many modifications of the basic configuration which can be used to solve special problems. Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer coefficient. The objective of this paper is to find the baffle spacing at fixed baffle cut that will give us the optimal values for the overall heat transfer coefficient. To do this Microsoft Excel 2003 package was employed. The results obtained from previous studies showed that to obtain optimal values for the overall heat transfer coefficient for the shell and tube heat exchangers a baffle cut of 20 to 25 percent of the diameter is common and the maximum spacing depends on how much support the tubes need. This was used to validate the results obtained from this study.

scholarly journals Shell-Side Pressure Drop in the Multi-Baffled Shell-and-Tube Heat Exchangers

1965 ◽  
Vol 8 (32) ◽  
pp. 644-651 ◽  
Author(s):  
Seikan ISHIGAI ◽  
Eiichi NISHIKAWA ◽  
Yoshiaki NAKAYAMA ◽  
Shigeo TANAKA ◽  
Ikuo SAIDA ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Heat Exchangers ◽  
Shell Side ◽  
Side Pressure ◽  
Shell And Tube

scholarly journals Performance Analysis and Design Optimization of Shell and Tube Heat Exchangers

2021 ◽  
Author(s):  
praveen math
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Pressure Loss ◽  
Fluid Flows ◽  
Hot Water ◽  
Flow Conditions ◽  
Shell Side ◽  
Shell And Tube ◽  
Side Flow

Abstract Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. The aim of this study is to experiment, validate and to provide design suggestion to optimize the shell and tube heat exchanger (STHE). The heat exchanger is made of acrylic material with 2 baffles and 7 tubes made of stainless steel. Hot fluid flows inside the tube and cold fluid flows over the tube in the shell. 4 K-type thermocouples were used to read the hot and cold fluids inlet and outlet temperatures. Experiments were carried out for various combinations of hot and cold water flow rates with different hot water inlet temperatures. The flow conditions are limited to the lab size model of the experimental setup. A commercial CFD code was used to study the thermal and hydraulic flow field inside the shell and tubes. CFD methodology is developed to appropriately represent the flow physics and the procedure is validated with the experimental results. Turbulent flow in tube side is observed for all flow conditions, while the shell side has laminar flow except for extreme hot water temperatures. Hence transition k-kl-omega model was used to predict the flow better for transition cases. Realizable k- epsilon model with non-equilibrium wall function was used for turbulent cases. Temperature and velocity profiles are examined in detail and observed that the flow remains almost uniform to the tubes thus limiting heat transfer. Approximately 2/3 rd of the shell side flow does not surround the tubes due to biased flow contributing to reduced overall heat transfer and increased pressure loss. On the basis of these findings an attempt has been made to enhance the heat transfer by inducing turbulence in the shel l side flow. The two baffles were rotated in opposite direction to each other to achieve more circulation in the shell side flow and provide more contact with tube surface. Various positions of the baffles were simulated and studied using CFD analysis and th e results are summarized with respect to heat transfer and pressure loss.

scholarly journals Structural And Thermal Characteristics of Aluminum Grades 6063 and 7075 with Application of Nano Coatings

2018 ◽  
Vol 7 (2.32) ◽  
pp. 187
Author(s):  
Ch Sridhar Yesaswi ◽  
N Venkata Sai ◽  
K Vivek ◽  
B Raju ◽  
G Venkat
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
Material Selection ◽  
Structural Characteristics ◽  
Thermal Characteristics ◽  
Vital Role ◽  
Nano Particles ◽  
Technology Advancement ◽  
Nano Coating ◽  
Metal Pipes

To fabricate any product, material selection is one of the major constraints for many engineers even on today. An intensive research is being done by scientists and engineers over the properties and characteristics of the materials. Due to the technology advancement, applications of various new products are entering into market with different materials. From the past few decades composites and alloy materials are playing a vital role because of their unique nature. In the present work heat exchangers are taken into application. In nuclear and power plants heat exchangers plays a crucial role in cooling the reactors. When these are made to cool with water by sending through metal pipes over a period of time, metal pipes get easily corroded because of water and thermal conductivity of the metal. When base metals are coated with Nano-particles there is a drastic change in their behavior. In this paper Aluminum grade 6063 and grade 7075 are considered and coated with Al2O3-NaOH Nano fluids. Their thermal and structural characteristics are identified before and after Nano coating.    

3-D Numerical Simulation of the Vapor-Liquid Flow at the Shell Side of Shell-and-Tube Heat Exchangers

2016 ◽  
Author(s):  
Qi Xiao ◽  
Ning Yang ◽  
Zhenxing Zhao ◽  
Chunhui Dai ◽  
Jun Wu ◽  
...  
Keyword(s):  
Liquid Flow ◽  
Heat Exchangers ◽  
Volume Fraction ◽  
Heated Wall ◽  
Bulk Temperature ◽  
Subcooled Boiling ◽  
Shell Side ◽  
Boiling Process ◽  
Shell And Tube ◽  
Vapor Liquid

The boiling vapor-liquid flow at the shell side of shell-and-tube heat exchangers was simulated by Euler-Euler transient 3D method in this paper. The mass and heat transfers between the two-phase fluid and heated wall for the subcooled boiling phenomenon were described by the Rensselaer Polytechnic Institute model (RPI model), while the steam condensation within the subcooled liquid was described by the Lee model. Firstly, different turbulence and interfacial force models were evaluated by comparing with the experimental data of Bartolomej (1982). It was found that the turbulence models have minor influence on the temperature and vapor volume fraction distributions. As the bubble size in the subcooled boiling process is small (usually <1 mm), the velocity slip between the vapor bubbles and the liquid is not so important. The simulation results using different drag force models are similar, and the Tomiyama model offers relatively better predictions. The non-drag forces could not significantly improve the accuracy in our simulations. Then the gas-liquid boiling flow at the shell side of shell-and-tube heat exchangers was then simulated. It was found that the water temperature increases almost linearly near the inlet zone, and the increase speed was slowed down when the bulk temperature approached to the saturated point as the boiling process happened more frequently and consumed much heat. The heat exchangers with the triangle and square configurations have similar temperature and vapor distributions. Further analyses for those two kinds of tube configurations are needed.

Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants

2015 ◽  
Vol 63 (1) ◽  
pp. 35-41 ◽  
Author(s):  
D. N. Ilmov ◽  
Yu. N. Mamontov ◽  
A. S. Skorohodov ◽  
V. A. Smolyarov ◽  
N. I. Filatov
Keyword(s):  
Energy Conversion ◽  
Heat Exchangers ◽  
Power Plants ◽  
Energy Conversion Systems

Effect of Temperature on Damping in Shell and Tube Heat Exchangers

2008 ◽  
Author(s):  
Ali Roheim El-Ghalban ◽  
Qamar Iqbal ◽  
Shahab Khushnood ◽  
M. Arshad Qureshi ◽  
M. Shahid Khalil
Keyword(s):  
Heat Exchangers ◽  
Design Procedure ◽  
Design Guidelines ◽  
Nuclear Industry ◽  
Major Influence ◽  
Shell Side ◽  
Flow Induced Vibration ◽  
Standard Design ◽  
Shell And Tube ◽  
Operating Temperatures

Flow-induced vibration in heat exchangers has been a key source of concern in the process, power generation and nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported. Design of tube bundles with loosely supported tubes in baffles for process shell and tube heat exchanger and steam generator needs estimation of energy dissipation mechanisms or damping for a safer and long term operation. Damping has a major influence on the flow induced vibrations and is dependant on a variety of factors such as mechanical properties of the tube material, geometry and number of intermediate supports, the physical properties of shell-side fluid, type of tube motion, tube frequency, shell-side temperature etc. Various damping mechanisms have been identified and quantified such as Friction damping, Viscous damping, Squeeze film damping, Support damping and Two-Phase damping which affect the performance with respect to flow induced vibration design, including standard design guidelines. But generally the effects of the higher operating temperatures on the various damping mechanisms are neglected in the general design procedure. The operating temperatures play significant role on the contribution of various damping mechanisms. The current paper focuses on the thermal aspects of damping mechanisms subjected to single phase cross-flow in process heat exchangers and formulates the design guidelines for safer design based on experimental and empirical formulations. The research results show that he increase in the temperature results in the increase of the damping. Moreover it found that the natural frequency is higher for lower mass flow rate and lower working pressures and lower temperatures.

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