Shellside Waterflow-Induced Tube Vibration in Heat Exchanger Configurations With Tube Pitch-to-Diameter Ratio of 1.42

1989 ◽  
Vol 111 (4) ◽  
pp. 441-449 ◽  
Author(s):  
H. Halle ◽  
J. M. Chenoweth ◽  
M. W. Wambsganss

The pitch-to-diameter ratio (P/D) of the tube layout in shell-and-tube heat exchangers is one of the major parameters with which the designer may control heat transfer and pressure drop and facilitate mechanical cleaning. As part of a comprehensive investigation of waterflow-induced tube vibration in an industrial-size research heat exchanger, various configurations characterized by different design parameters, including P/D ratio, had been investigated. To provide a comparison with previous data obtained with P/D = 1.25, this paper presents the results of a study of eight different tube bundle configurations with P/D = 1.42. Four equilaterally spaced tube layout patterns and two baffle edge orientations were investigated. The results indicate that the greater flow area of the P/D = 1.42 configuration increases flow penetration into the bundle, reduces the tube-to-tube vibration coupling and generally provides less well-defined, even though sometimes improved, fluidelastic instability thresholds.

2007 ◽  
Vol 129 (10) ◽  
pp. 1425-1431 ◽  
Author(s):  
B. Peng ◽  
Q. W. Wang ◽  
C. Zhang ◽  
G. N. Xie ◽  
L. Q. Luo ◽  
...  

Two shell-and-tube heat exchangers (STHXs) using continuous helical baffles instead of segmental baffles used in conventional STHXs were proposed, designed, and tested in this study. The two proposed STHXs have the same tube bundle but different shell configurations. The flow pattern in the shell side of the heat exchanger with continuous helical baffles was forced to be rotational and helical due to the geometry of the continuous helical baffles, which results in a significant increase in heat transfer coefficient per unit pressure drop in the heat exchanger. Properly designed continuous helical baffles can reduce fouling in the shell side and prevent the flow-induced vibration as well. The performance of the proposed STHXs was studied experimentally in this work. The heat transfer coefficient and pressure drop in the new STHXs were compared with those in the STHX with segmental baffles. The results indicate that the use of continuous helical baffles results in nearly 10% increase in heat transfer coefficient compared with that of conventional segmental baffles for the same shell-side pressure drop. Based on the experimental data, the nondimensional correlations for heat transfer coefficient and pressure drop were developed for the proposed continuous helical baffle heat exchangers with different shell configurations, which might be useful for industrial applications and further study of continuous helical baffle heat exchangers. This paper also presents a simple and feasible method to fabricate continuous helical baffles used for STHXs.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amin Farzin ◽  
Mehrangiz Ghazi ◽  
Amir Farhang Sotoodeh ◽  
Mohammad Nikian

Purpose The purpose of this study is to provide a method for designing the shell and tube heat exchangers and examine the total annual cost of heat exchanger networks from the economic view based on the careful design of equipment. Design/methodology/approach Accurate evaluation of heat exchanger networks performance depends on detailed models of heat exchangers design. The simulations variables include nine design variables such as flow direction determination of each of the two fluids, number of tubes, number of tube passes, length of tubes, the arrangement of tubes, size and percentage of baffle cut, tube diameter and tube pitch. The optimal designing of the heat exchangers is based on geometrical and hydraulic modeling and using a hybrid genetic particle swarm optimization algorithm (PSO-GA) technique. In this paper, optimization and minimization of the total annual cost of heat exchanger networks are considered as the objective function. Findings In this study, a fast and reliable method is used to simulate, optimize design parameters and evaluate heat transfer enhancement. PSO-GA algorithms have been used to minimize the total annual cost, which includes investment costs of heat exchangers and pumps, operating costs (pumping) and energy costs for utilities. Three case studies of four, six and nine streams are selected to demonstrate the accuracy of the method. Reductions of 0.55%, 23.5% and 14.78% are obtained in total annual cost for the selected streams, respectively. Originality/value In the present study, a reliable method is used to simulate and optimize design parameters and the economic optimization of the heat exchanger networks. Taking into account the importance of shell and tube heat exchangers in industrial applications and the complexity in their geometry, the PSO-GA methodology is adopted to obtain an optimal geometric configuration. The total annual cost is chosen as the objective function. Applying this technique to case studies demonstrates its ability to accurately design heat exchangers to optimize the objective function of the heat exchanger networks by giving the detail of design.


Author(s):  
N. F. Timerbaev ◽  
A. K. Ali ◽  
Omar Abdulhadi Mustafa Almohamed ◽  
A. R. Koryakin

In this article, a mathematical simulation of a double pipe heat exchanger is carried out, having the longitudinal rectangular fins with the dimension of (2*3*1000) mm, mounted on the outer surface of the inner tube of the heat exchanger. In this paper, the advantage of using of that type of fins and its effect on the effectiveness of the heat exchanger are studied with the help of the computer program. The carried out research allowsmaking the calculation to find the optimum design parameters of heat exchangers. The outer tube diameter is (34.1mm) while the inner tube diameter is (16.05mm). The tubes wall thickness is (1.5mm) and the model length was (1 m). The hot water is flowing through the inner tube in parallel with the cold water that passing the outer tube. The hot and cold water temperature at the inlet is (75°C & 30°C) respectively. The mass flow rate inside the central pipe is (0.1 kg/s) while the annular pipe carrying (0.3 kg/s). In the present work, the program ANSYS Workbench 15.0 was used to find out the results of heat transfer as well as the behavior of liquids inside the heat exchangers.


2021 ◽  
Author(s):  
praveen math

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.


1992 ◽  
Vol 114 (1) ◽  
pp. 124-131 ◽  
Author(s):  
F. Osweiller

For about 40 years most tubesheet exchangers have been designed according to the standards of TEMA. Partly due to their simplicity, these rules do not assure a safe heat-exchanger design in all cases. This is the main reason why new tubesheet design rules were developed in 1981 in France for the French pressure vessel code CODAP. For fixed tubesheet heat exchangers, the new rules account for the “elastic rotational restraint” of the shell and channel at the outer edge of the tubesheet, as proposed in 1959 by Galletly. For floating-head and U-tube heat exchangers, the approach developed by Gardner in 1969 was selected with some modifications. In both cases, the tubesheet is replaced by an equivalent solid plate with adequate effective elastic constants, and the tube bundle is simulated by an elastic foundation. The elastic restraint at the edge of the tubesheet due the shell and channel is accounted for in different ways in the two types of heat exchangers. The purpose of the paper is to present the main basis of these rules and to compare them to TEMA rules.


Author(s):  
A.A. Aleksandrov ◽  
I.V. Barmin ◽  
A.V. Zolin ◽  
V.V. Chugunkov

The paper describes the propellant cooling system using liquid nitrogen and a combination of recuperative heat exchangers, including sections of the double pipe heat exchanger and a twisted heat exchanger located in a tank with antifreeze, cooled by nitrogen gas coming out of the sections of the double pipe heat exchanger. Mathematical models of cooling processes for two variants of movement of propellant and liquid nitrogen in the channels of the double pipe heat exchanger sections are considered. Their using makes it possible to analyze the efficiency of propellant cooling operations depending on its mass, design parameters of the system tanks and heat exchangers, consumption characteristics of nitrogen and propellant, as well as to predict the required mass of liquid nitrogen and the time of propellant cooling during the operation of launching complex propellant-feed systems. Calculated dependences and simulation results of propellant and antifreeze cooling in a tank with a twisted heat exchanger are presented. The influence of variants of arranging propellant cooling processes and liquid nitrogen consumption on the efficiency of the cooling system is analyzed. Comparing to the available systems the capability of reducing the cost of liquid nitrogen are identified as well as reducing time of the propellant cooling operations by means of equipping launch complexes.


1973 ◽  
Vol 95 (1) ◽  
pp. 145-150 ◽  
Author(s):  
L. J. Wolf ◽  
R. M. Mains

Expansion joints of the style most commonly used in shell and tube heat exchangers were studied analytically and experimentally in the elastic range. A method of computing stresses and deformations for pressure and expansion loadings is demonstrated. Strain-gage tests show the analytical method to be accurate.


2015 ◽  
Vol 10 (2) ◽  
pp. 81-96 ◽  
Author(s):  
Sandip K. Lahiri ◽  
Nadeem Muhammed Khalfe

Abstract Owing to the wide utilization of shell and tube heat exchangers (STHEs) in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change the design and geometric parameters until satisfying a given heat duty and set of geometric and operational constraints. Although well proven, this kind of approach is time-consuming and may not lead to cost-effective design. The present study explores the use of non-traditional optimization technique called hybrid particle swarm optimization (PSO) and ant colony optimization (ACO), for design optimization of STHEs from economic point of view. The PSO applies for global optimization and ant colony approach is employed to update positions of particles to attain rapidly the feasible solution space. ACO works as a local search, wherein ants apply pheromone-guided mechanism to update the positions found by the particles in the earlier stage. The optimization procedure involves the selection of the major geometric parameters such as tube diameters, tube length, baffle spacing, number of tube passes, tube layout, type of head, baffle cut, etc. and minimization of total annual cost is considered as design target. The methodology takes into account the geometric and operational constraints typically recommended by design codes. Three different case studies are presented to demonstrate the effectiveness and accuracy of proposed algorithm. The examples analyzed show that the hybrid PSO and ACO algorithm provides a valuable tool for optimal design of heat exchanger. The hybrid PSO and ACO approach is able to reduce the total cost of heat exchanger as compare to cost obtained by previously reported genetic algorithm (GA) approach. The result comparisons with particle swarm optimizer and other optimization algorithms (GA) demonstrate the effectiveness of the presented method.


Author(s):  
Majid Amidpour ◽  
Abazar Vahdat Azad

In this paper, the new approach of Constructal theory has been employed to design shell and tube heat exchangers. Constructal theory is a new method for optimal design in engineering applications. The purpose of this paper is optimization of shell and tube heat exchangers by reduction of total cost of the exchanger using the constructal theory. The total cost of the heat exchanger is the sum of operational costs and capital costs. The overall heat transfer coefficient of the shell and tube heat exchanger is increased by the use of constructal theory. Therefore, the capital cost required for making the heat transfer surface is reduced. Moreover, the operational energy costs involving pumping in order to overcome frictional pressure loss are minimized in this method. Genetic algorithm is used to optimize the objective function which is a mathematical model for the cost of the shell and tube heat exchanger and is based on constructal theory. The results of this research represent more than 50% reduction in costs of the heat exchanger.


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