Number Of Tube Rows Research Articles

Thermodynamic performance of air-cooled seasonal cold energy storage for space cooling: A case study

With the improvement in people's living standards, there is a growing demand for cooling, making it urgent to develop a low-carbon and energy-efficient refrigeration system. Therefore, this paper proposes an air-cooled seasonal energy storage (ACSES) system. The heat transfer model of the system is constructed. The impact of relevant parameters on the system's cold storage performance was analyzed. The results show that larger glycol flow rates, windward velocity, number of tube passes and tube rows, and the volume ratio of ethylene glycol to water (VR) are beneficial for improving cold storage performance. However, excessively large parameters do not significantly enhance cold storage performance. The influence of ambient temperature on cold storage performance is greater than that of ice thickness. When VR is 0.02, the cold storage performance is relatively superior. To demonstrate the energy-saving performance of the system, the energy consumption saving rate (ECSR) indicator was proposed. The ECSR of the ACSES system is 72.75 %. The system can significantly conserve resources and reduce energy consumption.

A simplified numerical method based on anisotropic porous media model for the precooler of the hypersonic precooled engine

The precooler is a key component of hypersonic precooled engine, and its actual structural have a high anisotropy in the axial, circumferential, and radial direction. Considering the non-uniform flow inside the precooler is crucial to study the flow and heat transfer characteristics of the precooler. The previous simplified method for the precooler has not fully considered the flow non-uniformity of the axial, radial and circumferential direction. In this paper, a simplified numerical method based on anisotropic porous media model for the precooler was proposed. The unique aspect of this method is the integration of anisotropic surface porosity of porous media model with the zero-dimensional heat transfer model. In addition, the influence of key structural parameters on the flow and heat transfer characteristics of precooler was studied. It is found that as the tube transverse pitch increases from 2 to 3.5, the total flow rate increases by 11%, and the heat exchange rate decreases by 25%. As the number of tube rows increases from 7 to 13, the heat exchange rate increases by 22%, but the total pressure loss coefficient increases from 0.046 to 0.082. In addition, the decrease of inner diameter of the precooler improves the heat exchange rate, but reduces the flow capacity of the precooler. These results indicate that the simplified numerical method is capable of simulating the behavior of precooler and provides some guidance on the design of precooler.

Optimization strategies for the design of pre-cooler based on the synergistic air-breathing rocket engine

A foundation for the engineering of pre-coolers is provided to understand the flow and heat transfer characteristics of air pre-coolers. Using the pre-cooler in the combustor of the Synergistic Air-Breathing Rocket Engine (SABRE) as the research object and selecting the smallest periodic unit of the model, numerical methods were adopted to study the flow field, outlet temperature, total pressure loss, heat transfer coefficient, and heat transfer power under the different number of tube rows, pitch, and helium/air heat capacity ratios. The number of tube rows increased from 7 to 15, the tube pitch increased from 1.5 mm to 3.5 mm, and the helium/air capacity ratio increased from 1.06 to 1.64. The results show that increasing the tube pitch reduces the outlet velocity and decreases the heat exchange efficiency, but the total pressure loss is reduced. Increasing the number of tube rows results in a linear increase in total pressure loss, but the heat exchange efficiency also increases. The increasing trend slows down when the number of tube rows exceeds 11. An increase in the heat capacity ratio can reduce the total pressure loss, increase the heat exchange power, and increase the amount of helium required. It can provide a reliable technical foundation for the practical engineering design of similar pre-coolers.

Numerical analysis of the heat transfer and pressure drop of a wavy fin and Kammtail tube condenser: An investigative study

The aim of this study was to numerically investigate the factors affecting the air-side performance of an innovative condenser for a domestic refrigerator. Novel condenser with a smooth Kammtail tube form was investigated due to delaying flow separation. For the first time in the literature, the kammtail form was used instead of round or ellipse geometry in a finned tube heat exchanger, and the advantages of this form was demonstrated both experimentally and numerically. This study incorporated design parameters such as air velocity (0.5, 0.7, 1 m/s), number of tube rows (4 or 5), tube arrangement (inline, staggered), fin pitches (5, 7, 10, 5–7, 5–10, 7–10 mm), and fin arrangement (homogeneous or hybrid). The findings indicated that, for identical fin types and fin surface areas, the proposed Kammtail shape of 3 × 6 mm exhibited 19% lower pressure drop and 9% higher heat-transfer coefficient compared to the original circular tube profile. Furthermore, decreasing the fin pitches resulted in a 32.9–97% increase in static pressure drop, while the heat-transfer coefficient decreased by about 4.7–11.7%. The examination of two new designs revealed a marked reduction of 7–20.4% in the static pressure drop, a decline in air flow rate of 30%, an increase in heat transfer of 5.6–12.2%, and a corresponding decrease in the volume of the condenser of 20%. The numerical results of this study are in good agreement with experimental results, with deviations of less than 10%.

Multi-Objective Finned-Tube Heat Exchanger Optimization Using a Genetic Algorithm

Heat exchangers are a significant component in many industries, particularly in energy conversion systems. The design of heat exchangers itself is a complex process because it involves experience-based decisions, numerous variables and parameters, and some of them are competing with each other. Genetic Algorithms (GAs) are one of the first evolutionary algorithms which remains one of the most extensively used non-linear optimization methods today. This study explores the implementation of Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for thermal design and optimization of a finned-tube heat exchanger. The chosen objective functions were minimizing the heat exchanger volume and minimizing the air side pressure drop. The decision variables for the design were tube outer diameter, number of tube rows, fin pitch, unit height, and unit width. The calculated parameters and estimated cost of both preliminary design and optimized design were also compared. The optimized design offered a bigger alternative design while meeting all the constraints according to standards and industrial needs. The optimization reduced annualized operational and maintenance costs by 228% and lowered air pressure drop by 413% with bigger heat exchanger volume of 12% compared to the preliminary design.

Experimental study on the external resistance of vertical tube indirect evaporative coolers

To address the calculating difficulty of external resistance of vertical tube in the widely used indirect evaporative coolers, this paper experimentally investigates the influencing factors of the tube external resistance and develops calculation formula for tube external resistance. An experimental setup was constructed to test the external resistance of different numbers of tube rows at wind speeds of 1 m/s, 1.5 m/s, 2 m/s, 2.5 m/s, and 3 m/s. A specific vertical tube indirect evaporative cooler with a tube diameter of 25 mm, tube-to-tube center distance of 35 mm, and row-to-row center distance of 30 mm was studied. It was found that the tube external resistance of the studied cases is mainly affected by the face wind speed and the number of tube rows. Based on the response surface method (RSM), a formula for calculating the tube external resistance was fitted using the measured data, which provides guidance for engineering applications of vertical tube type indirect evaporative coolers.

Experimental study on performance improvement of a household refrigerator with a flying-wing evaporator

In order to improve the performance of a household refrigerator, a flying-wing evaporator (FWE) is to replace the original finned tube evaporator (FTE). Different from the FTE, the fins of the FWE are formed directly on the tube by shoveling movement. Therefore, the FWE has high efficient heat transfer performance due to no thermal contact resistance between the tubes and the fins. According to different combinations of fin pitch and number of tube rows, three different structures of FWE are designed and tested in comparison with the original FTE on a double-door household refrigerator. The results show that the FWE shortens the cooling duration by 0.32 h (9.3%) and reduces the annual energy consumption by 4.28% with a 25% reduction in volume and a 13.5% reduction in refrigerant charge. This study proves that applying a FWE into a household refrigerator instead of the traditional FTE is one of the effective ways to decrease the volume of evaporator, reduce the energy consumption of refrigerator and enhance the effect of food preservation.

Study on Heat Transfer Performance and Parameter Improvement of Gravity-Assisted Heat Pipe Heat Transfer Unit for Waste Heat Recovery from Mine Return Air

One of the effective methods for energy conservation and emission reduction in coal mines is to utilize waste heat recovery technology to recover mine return air waste heat. The gravity heat pipe is widely used in mine return air waste heat recovery due to its sustainable and economic advantages, but its heat transfer is a complex process influenced by multiple parameters. A single-tube heat transfer resistance model and a heat transfer calculation model based on enthalpy difference were established for the heat exchange tubes. Four typical application cases of a low flow rate and a low number of tube rows were selected, and their heat transfer characteristics were tested onsite and analyzed. It was found that there were problems such as a low overall heat transfer efficiency, a low fresh air outlet temperature, and a risk of icing in the final tube section. The effects of the gravity heat pipe parameters on the heat transfer performance were studied, such as the tube outer diameter, tube spacing, and the finned tube outer diameter. It was found that the air-resistant force of the heat exchanger increased with the increase of the tube spacing and the finned tube outer diameter, the heat transfer resistance increased with the increase of the tube spacing and the decrease of the finned tube outer diameter, and the heat transfer coefficient first increased and then decreased with the increase of the tube outer diameter. A configuration improvement scheme with a high flow rate and a high number of tube rows is proposed here. Taking Case 2 as an example, the temperature distribution of the heat tube before and after improvement is compared and analyzed. The results show that the heat transfer performance of the heat exchange system significantly improved. Without increasing the air resistance of the heat tube, the temperature of the return air outlet after improvement was reduced to 1.1 °C, 4.1 °C lower than that before improvement, further recovering the waste heat of the mine return air. The temperature of the condensate water film was greater than 0.5 °C, avoiding the icing problem of the condensate tube section, the fresh air outlet temperature reached 5.2 °C, an increase of 7.8 °C compared to that before improvement, and the overall heat transfer efficiency increased from 56.7% to 66%.

Numerical analysis of vibration response of elastic tube bundle of heat exchanger based on fluid structure coupling analysis

Abstract A tube bundle heat exchanger is a typical heat exchange equipment that exchanges heat between two fluids with different temperatures. Through this equipment, one fluid can be cooled down and another fluid can be heated up to meet their respective needs. The equipment is widely used in chemical, petroleum, pharmaceutical, energy, and other industrial sectors, and is one of the indispensable and important equipments in chemical production. To improve the heat transfer performance and service life of the heat exchanger, a numerical analysis of the vibration response of the elastic tube bundle in the heat exchanger based on fluid–structure coupling analysis is proposed. Using the weak coupling method of fluid–structure coupling, the vibration response of multiple rows of elastic tube bundles induced by shell side fluid in a heat exchanger with different tube row spacing and different tube row numbers is studied numerically, and the effects of shell side fluid and tube side fluid on the vibration response of elastic tube bundles are compared and analyzed. The results show that the maximum relative error of monitoring point amplitude is 43.36% when H = 40 mm and 10.17% when H = 70 mm. For connection IV, the maximum relative error of monitoring point amplitude is 31.71% when H = 40 mm and 24.08% when H = 70 mm. This is because when H is small, the interaction between rows of tube bundles is strong, so the amplitude changes violently with the number of the tube bundle. The step-by-step calculation strategy of rough calculation and actuarial calculation proposed in this article can greatly reduce the calculation time and improve the calculation efficiency.

Effect of Tube Rows on Two-Phase Heat Transfer Characteristics of Water Over Staggered Tube Bundles Under Flow Boiling Mode

Abstract Tube bundles are an integral part of the two-phase heat exchangers and are employed in numerous commercial applications. Present research compares two kinds of horizontal staggered tube bundles under upward crossflow boiling to see how tube rows affect the heat transfer coefficient (HTC). The experimental setup developed houses the tube bundle for temperature measurements and facilities the recording of high-speed images at different operating conditions. The investigation is carried out for heat fluxes of 10–75 kW/m2, mass fluxes of 20–100 kg/m2s, and P/D ratios of 1.25, 1.6, and 1.95, with distilled water as the working fluid. It is observed that both tube bundles show an increase in overall HTC with an increase in heat flux. However, the 5 × 3 tube bundle resulted in a greater heat transfer rate as compared to the 2 × 3 tube bundle due to the bundle effect. Further, both tube bundles have a diminishing trend of HTC with a rise in mass flux. The rate of rising in HTC was found to decrease with an increase in the number of tube rows in the tube bundle and with an increase in the P/D ratio. Therefore, interestingly it is observed that the increase in bundle average HTC of 5 × 3 tube bundle is not twice that of 2 × 3 tube bundle rather it is quite lesser which further deteriorates with an increase in P/D ratio. The row-wise and bundle average HTC obtained is also predicted with a dimensionless correlation within an error of ± 15%.

Numerical study of the cold finned-tube bundle heat exchanger under natural convection for a novel passive displacement cooling system

In a passive displacement cooling (PDC) system, conventional finned-tube heat exchangers are being employed and their performance is not optimal under natural convection. In this study, an experimental set-up has been established to validate the numerical model for finned-tube heat exchanger optimization under natural convection. The numerical difference between the predicted and measured data is less than 3.4%, showing that the numerical model could predict the heat transfer and flow rate accurately under natural convection. Subsequently, the effects of fin spacing, coil configuration, tube row number, and fin depth on the coil performance under natural convection have been investigated. The results show that the one-row coil performs better than the two-row coil for a PDC system with 8-10 fins per inch (FPI), despite the smaller heat transfer area. Compared with the conventional two-row circular-tube coil with 10FPI, the one-row circular-tube coil improves the mass flow rate and heat transfer rate by around 29.1% and 20.0% respectively. The findings enable a more responsive and energy-efficient PDC system for green buildings.

New correlations for predicting convective heat transfer of single and multi-row heat exchangers employing staggered drop-shaped tubes

In this paper, for the first time, air-side correlations were developed and introduced to describe the average Nusselt number Nu¯, friction factor f, and thermal−hydraulic performance ε of compact heat exchanger employing drop-shaped tubes considering the number of tube rows (NR). Drop-shaped tubes were arranged in a staggered formation and placed in 1 to 20 consecutive rows in the flow direction, each consisting of 7 tubes in the transverse direction. The Reynolds number (Re) varied from 1.78 × 103 to 18.72 × 103. The calculations were carried out using Ansys Fluent software package. Tube row and Reynolds number effects on the thermal and hydrodynamic characteristics of the studied heat exchangers were analyzed. The simulation results were in a good agreement with the available literature. The results showed that Nu¯ and ε increase, while f decreases as Re increases. Moreover, an increase in NR leads to an increase of f and a decrease of ε. The maximum values of Nu¯ were obtained for NR = 2, which were higher by 3.95–6.69% and 19.91–24.62% than those for NR= 1, and NR= 20, respectively. Heat transfer was stabilized only from the 19-row onwards. In addition, a 1-row heat exchanger had better thermal−hydraulic performance compared to that with a larger NR (ε for NR = 1 was about 22.32–27.24 times higher than those for NR = 20). The maximum deviation between the numerical results and the obtained correlations developed from them was ±8.87%, which provides a useful reference for future studies and designs of heat exchangers with different row numbers of drop-shaped tubes.

Parametric Study on Thermal-Hydraulic Characteristics of H-Type Finned Tube Heat Exchangers

In this paper, the thermal-hydraulic characteristics of H-type finned tube banks are numerically investigated on the basis of a more accurate and convenient calculation method of fin efficiency for H-type fins. Experiments are performed to validate the numerical simulations. The variations of the Nusselt number, Euler number, and comprehensive factor with the Reynolds number and seven geometric parameters of H-type finned tube banks are obtained. The results indicate that the Nusselt number is proportional to the Reynolds number, the slit width, the fin thickness, and the longitudinal tube pitch; but, it is inversely proportional to the tube row number, the fin height, and the spanwise tube pitch. As the Reynolds number, the tube row number, the slit width, the fin pitch, and the spanwise tube pitch increase, the Euler number decreases. The factor rises with the increase of the slit width, and there exists an optimal tube row number () at which the factor is the maximum. The correlations of the heat transfer (Nusselt number) and pressure drop (Euler number) of the 10-row H-type finned tube bank, which can nearly be considered to be fully developed, are presented. The numerical results and correlations have good applicability under different fluids and show good agreement with the experimental results and correlations.

Numerical investigation of slit fin at different Reynolds numbers: A sensitivity analysis and optimization by Taguchi methodology

The parametric study is carried out by Taguchi methodology, including twenty-seven cases with different combinations of key parameters, involving Reynolds number(Re), transverse pitch(Pt), longitudinal pitch(Pl), number of tube rows(N) and fin pitch(Fp). Firstly, the distributions of heat flux and shear stress are displayed. The heat flux decreases sharply along the flow direction, but the distribution of shear stress in front row is almost same to that in rear row. Secondly, the analysis of variance(ANOVA) is carried out, which indicates that Re is the most sensitive parameter on j-factor and f-factor, and its statistical significance is much greater than that of structural parameters. Furthermore, the sensitivity analyses of structural parameters at different Re are performed. For j-factor, the contribution ratio of Fp is the biggest at Re = 900, the contribution ratio of N is the biggest at Re = 1800 or Re = 2700. For f-factor, the contribution ratio of Fp is the biggest at Re = 900, the contribution ratio of Pl is the biggest at Re = 1800 or Re = 2700. For comprehensive performance, the contribution ratio of N has always been the biggest at different Re. Finally, the optimal combination of structural parameters is obtained, and its comprehensive performance is improved by 2.73%–3.23% at different Re.

Comparison of Individual Air-Side Row-By-Row Heat Transfer Coefficient Correlations on Four-Row Finned-Tube Heat Exchangers

Each row of the heat exchanger (HEX) has different hydraulic-thermal characteristics. When the air velocity upstream of the HEX is lower than approximately 3 m/s, the exchanged heat flow rates at the first rows of tubes are higher than the average value for the entire HEX. The article presents the determination of the individual correlations for the air-side Nusselt numbers on each row of tubes for a 4-row finned HEX with continuous flat fins and round tubes in a staggered tube layout. The method was built based on computational fluid dynamics modeling. Mass average temperatures for each row were simulated for over a dozen different airflow velocities, from 2.5 m/s to 10 m/s. The obtained individual correlations for the air-side Nusselt number will enable selecting the optimum number of tube rows for a given heat output of the HEX. The investment costs of the HEX can be reduced by decreasing the tube row number. Moreover, the operating costs of the HEX can also be lowered, as the air pressure losses on the HEX will be lower, which in turn enables the reduction of the air fan power.

Air-Side Nusselt Numbers and Friction Factor’s Individual Correlations of Finned Heat Exchangers

Currently, when designing finned heat exchangers (FHE), the average value of the entire heat transfer coefficient (HTC) is considered. However, each row of the heat exchanger (HEX) has different hydraulic-thermal characteristics. The novelty of this research is to present the differentiation of the individual air-side Nusselt number and Darcy-Weisbach friction factor correlations in each row of FHE using CFD modelling. FHE has four-rows, circular tubes, and continuous fins with a staggered tube arrangement. Relationships for the Nusselt number and D-W friction factor derived for the entire exchanger based on CFD modelling were compared with those available in the literature, determined using experimental data. The maximum relative differences between the Nusselt number for a four-row FHE determined experimentally and by CFD modelling are in the range from 22% for a Reynolds number based on a tube outside diameter of 1000 to 30% for a Reynolds number of 13,000. The maximum relative differences between the D-W friction factor for a four-row FHE determined experimentally and by CFD modelling are in the range of 50% for a Reynolds number based on a tube outer diameter of 1000 to 10% for a Reynolds number of 13,000. The CFD modelling performed shows that in the range of Reynolds numbers based on hydraulic diameters from 150 to 1400, the Nusselt number for the first row in a four-row FHE is about 22% to 15% higher than the average Nusselt number for the entire exchanger. In the range of Reynolds number changes based on hydraulic diameter from 2800 to 6000, the Nusselt numbers on the first and second rows of tubes are close to each other. Correlations of Nusselt numbers and D-W friction factors derived for individual tube rows can be used in the design of plate-fin and tube heat exchangers used in equipment such as air-source heat pumps, automotive radiators, air-conditioning systems, and in air hot-liquid coolers. In particular, the correlations can be used to select the optimum number of tube rows in the exchanger.

Sensitivity analysis of structural parameters of a low-temperature heat pump sludge drying system

Optimizations of the heat exchanger of the heat pump drying system were usually carried out individually, linkage effect of the whole system in practical operating was usually not considered. In addition, for a heat pump sludge drying system, optimizations mainly concentrated on the operation parameters, few theoretical analyses focused on the effect of structural parameters to the system performance. In the present study, based on the laws of energy conservation and mass conservation, a steady-state model for the heat pump sludge drying system, which interconnects the refrigerant circulation and the moist air circulation, was established. Three variables which are coefficient of performance (COP), dehumidification rate (DR), and specific moisture extraction rate (SMER) are simultaneously introduced to evaluate the system’s operating and drying performances. Effects of the number of horizontal tube rows, the number of longitudinal tube rows, and the fin spacing to the above three variables are analyzed. The results show that the COP decreases with increasing the number of horizontal tube rows while increases with increasing the number of longitudinal tube rows and fin spacing. The DR increases with increasing the number of horizontal tube rows and fin spacing and decreases with increasing the number of longitudinal tube rows. The SMER has a similar variation trend to that of the DR due to their directly proportional relationship. Finally, based on the sensitivity analysis, the heat pump sludge drying system achieves better operating and drying performances when the fin spacing is 2.85 mm, the numbers of horizontal tube rows of the evaporator and condenser are 18 and 14, and the numbers of longitudinal tube rows are respectively 12 and 9.

Parametric and design optimization investigation of a wavy fin and tube air heat exchanger using the T‐G technique

AbstractThe focus of this paper is to optimize the air‐side performance of a wavy fin and tube heat exchanger at different design parameters on an individual target response using the Taguchi method. However, a statistical concept, gray relational analysis, is also studied for combined optimization, considering all target responses at a time. Based on the heat exchanger requirement, parametric study for the air‐side is regarded as a more significant heat transfer and lower frictional factor. Experimental correlations were available and used for the 27 orthogonal runs. Investigation revealed the highest 47.06% fin pitch, 37.24% fin pitch, 25.46% air velocity, and 23.9% fin thickness contribution ratio for the target response of friction factor (TPF), heat transfer coefficient, and Colburn factor, respectively, with the application of the Taguchi method in a heat exchanger. GRG gives an optimum set of design parameters, A3B3C2D1E3F2G1, for wavy fin and tube of fin pitch of 6 mm, tube row number of 6, waffle height 1.8 mm, fin thickness 0.12 mm, and air velocity 5 m/s. Also, longitudinal tube pitch is 27.5 mm, and transverse tube pitch of 24.8 mm, at which TPF is maximum while the friction factor is minimal. The Colburn factor is the most significant, minor friction factor, and the heat transfer coefficient and TPF are the most considerable in GRG. Hence, an improved heat transfer performance design of a wavy fin and tube heat exchanger is achieved using the above techniques.

Experimental investigation of heat transfer and pressure drop of fin and tube heat exchanger under dry and wet conditions

The heat transfer and pressure drop characteristics of nine flat plate finned tube heat exchangers have been experimentally investigated under dry and wet conditions. The effect of five parameters is evaluated for wet conditions: number of tube row (2, 4, 6), fin pitch (2, 3, 4 mm), frontal air velocity (1, 2, 3 m/s), temperature (25, 30, 35 °C), and relative humidity (60, 70, 80). The Box-Behnken Design (BBD) is used to determine minimum candidate test points of the experimental studies, and more experiments have been carried out to determine the effects more sensitively. For nine heat exchangers, the effect of frontal air velocity (1, 2, 3 m/s) is evaluated for dry conditions. (The Reynolds number ranged from 300 to 2150 for both conditions.) Response Surface Model (RSM) has been used to evaluate the Colburn j factor and Fanning friction f factor for dry and wet conditions. The results show that the j factor decreases with increasing front air velocity and number of tube rows, while the j factor increases with increasing fin pitch, air temperature, and relative humidity for wet conditions. In addition, the f factor decreases with increasing front air velocity, number of tube rows and fin pitch, while the f factor increases with increasing air temperature and relative humidity. For dry conditions, the j factor decreases with increasing front air velocity and number of tube rows, while the j factor increases with increasing fin pitch. In addition, the f factor decreases with increasing front air velocity, number of tube rows, while the f factor increases with increasing fin pitch. The j factor and f factor values are higher under wet conditions than dry conditions.Three correlations are proposed for the j and f factors under dry and wet conditions. For wet conditions, the best mean deviation for the j factor is 8.3%, whereas the best mean deviation for the f factor is 10.9%. For dry conditions, the best mean deviation for the j factor is 8.3%, whereas the best mean deviation for the f factor is 8.2%. The experimental results are compared with the proposed and literature correlations.Compared to the correlations obtained in literature studies using similar geometric parameters in the study, the proposed correlation has gave better results. Even at the values of geometric parameters which literature correlations are failed, the proposed correlations has gave good results.

Improved Design and Thermo-Mechanical Verification of Deflection Magnet Beam Collimator of EAST-NBI System

The deflection magnet (DM) is the most important component of the Neutral Beam Injection (NBI) system of Experimental Advanced Superconducting Tokamak (EAST), which can magnetically deflect the un-neutralized charged particles after the neutralized process of the beam is extracted from the ion source, and then form a neutral beam injected into the tokamak. Under the operating conditions of the NBI system, by using the thermocouple monitoring system in the experiment, it can be found that the currently operating DM beam collimator has a quite high temperature rise. It is necessary to redesign the DM beam collimator to improve its heat transfer performance. The parallel arrangement of multiple rows of tubes is proposed as the basic method for the redesign of the beam collimator of DM, the thermal-fluid-structure analysis model of this redesign model is established and its temperature field, pressure field and stress field are analyzed. Taking the surface temperature of the beam collimator, the overall dimension after the total tube combination and the pressure drop of the whole structure of collimator as the optimization objectives, and setting the fluid velocity, the tube’s inner diameter and the number of tube rows as the design variables, the optimized design scheme of the beam collimator structure is obtained. From the results of simulation, the new structure can better meet the operation requirements of DM, and its maximum temperature rise is well controlled, which is expected to meet the long pulse operation requirements of the NBI system. The proposed simulation and design optimization method can provide a certain reference for the design and optimization of other high-heat-flux structures in complex large-scale neutral beam systems in the future.