Pipe Diameter Ratio Research Articles

Predicting Manhole Mixing Using a Compartmental Model

Manholes in combined sewers may become surcharged during storm events, resulting in complex mixing conditions. Although manhole hydrodynamics are reasonably well understood, predicting mixing across a surcharged manhole remains a challenge. An analytical compartmental mixing model for manholes, based on jet theory, has been further developed and applied to generate cumulative residence time distributions (CRTDs), which describe mixing. The modeled CRTDs were compared with the experimentally derived CRTDs of over 850 manhole configurations to evaluate how well the new compartmental model represents physical processes. The model underpredicts short-circuiting in manholes with manhole diameter to pipe diameter ratios greater than 4.4 and consequently overestimates mixing. Otherwise, the modeled CRTDs show good agreement with the experimental CRTDs. The new compartmental model represents key manhole hydrodynamics that are not represented in current software modeling packages, which assume manholes are instantaneously well-mixed. The compartmental model provides good predictions of the experimental downstream concentration profiles, although with reduced peak concentrations in those manhole configurations where short-circuiting is not well-predicted. Despite this, the compartmental model still predicts concentrations downstream of a manhole in closer agreement with the recorded data than the complete instantaneously well-mixed assumption. As an analytical model requiring no inputs other than manhole geometry, the new compartmental model applies to a wide range of manhole configurations, is robust, and is useful for predicting manhole mixing in practical applications.

Computational fluid dynamic simulations to improve heat transfer in shell tube heat exchangers

Abstract Improving the thermal efficiency of shell-tube heat exchangers is essential in industries related to these heat exchangers. Installing heat transfer boosters on the side of the converter tube is one of the most appropriate ways to enhance heat transfer and increase the efficiency of this equipment. In this article, spring turbulence is studied using the computational fluid dynamics tool. The displacement heat transfer coefficient and the friction coefficient were selected as the primary target parameters, and the effect of using spring tabulators on them was investigated. The ratio of torsion step length to turbulence pipe length, wire diameter to pipe diameter ratio, and flow regime was studied as the main simulation variables, and the simulation results were compared with a simple pipe. The effect of water-acting fluid, R22, and copper Nanofluid on tubes containing turbidity was compared and investigated. This study showed that due to the pressure drop, the pipe with a torsional pitch to pipe length ratio of 0.17, a turbulent diameter to pipe diameter ratio of 0.15, and a Reynolds number of 50,000 with fluid R22 has the best performance for heat transfer.

Validation and assessment of different RANS turbulence models for simulating turbulent flow through an orifice plate

In the present study, numerical simulations using different Reynolds-Averaged Navier–Stokes (RANS) turbulence models are carried out to investigate the turbulent flow through the orifice plate at Reynolds number (Re) of 23000. The orifice thickness to pipe diameter ratio (t) and the orifice diameter to pipe diameter ratio (β) are fixed and equal to 0.1 and 0.5, respectively. The objective is to evaluate the behaviour of various RANS models with respect to the relevant flow parameters such as the pressure drop, velocity distributions and turbulence intensity profiles in the pipe by comparing the results with available published experimental data. The following turbulence models are studied: the k – ε, the k – ε Low Re, the k – ε RNG, the k – ε Realizable, the k – ω SST, the γ – SST, the EARSM and the k – ε Cubic models. It is found that based on the validation study of the flow through the orifice plate, the following models are in good agreement with experimental measurements: the k – ω SST, the γ – SST and the EARSM. They show a better performance than the k – ε model family in predicting the flow features which are important for the orifice flowmeter design.

Predicting oil flow rate through orifice plate with robust machine learning algorithms

Measuring fluid flow rate passing through pipelines is a basic strategy for developing the infrastructure of fluid-dependent industries. It is a challenging issue for trade, transportation, and reservoir management purposes. Predicting the flow rate of fluid is also regarded as one of the crucial steps for the development of oil fields. In this study, a novel deep machine learning model, convolutional neural network (CNN), was developed to predict oil flow rate through orifice plate (Qo) from seven input variables, including fluid temperature (Tf), upstream pressure (Pu), root differential pressure (√ΔP), percentage of base sediment and water (BS&W%), oil specific gravity (SG), kinematic viscosity (ν), and beta ratio (β, the ratio of pipe diameter to orifice diameter). Due to the absence of accurate and credible methods for determining Qo, deep learning can be a useful alternative to traditional machine learning methods. Justifying the promising performance of the developed CNN model over conventional machine learning models, three different machine learning algorithms, including radial basis function (RBF), least absolute shrinkage and selection operator (LASSO), and support vector machine (SVM), were also developed and their prediction performance was compared with that of the CNN model. A sensitivity analysis was also performed on the influence degree of each input variable on the output variable (Qo). The study outcomes indicate that the CNN model provided the highest Qo prediction accuracy among all the four models developed by presenting a root mean squared error (RMSE) of 0.0341 m3/s and a coefficient of determination (R2) of 0.9999, when applied to the dataset of 3303 data records compiled from oil fields around Iran. The Spearman correlation coefficient analysis results display that √ΔP, Pu, and Tf were the most influential variables on the oil flow rate in respect of the large dataset evaluated.

Stability assessment of the phase-field lattice Boltzmann model and its application to Taylor bubbles in annular piping geometries

This study parametrically assessed the stability of the phase-field lattice Boltzmann model (PFLBM) before applying it to analyze the effect of annular piping geometry on the flow of Taylor bubbles. The impacts of both eccentricity and pipe diameter ratio were examined, providing an insight into the behavior of these bubbles as well as the applicability and shortcomings in current prediction methodologies. A recently developed PFLBM was implemented into the open-source simulation framework, waLBerla, for this analysis. The stability properties of the code were investigated in detail by assessing various lattice discretizations and relaxation kernels applied to the Rayleigh–Taylor benchmark problem and a Rayleigh–Taylor instability in a tubular geometry, with gravitational Reynolds numbers of up to 30 000 and 10 000, respectively. This paper makes three contributions relating to the stability and usage of the PFLBM as well as the flow of Taylor bubbles in annular pipes. First, the work numerically explored the stability properties of the velocity-based, PFLBM and concluded the impact of various collision models and lattice discretizations on simulation results. Second, it provided a flexible open-source code that the interested researcher can use interactively for practical flow problems as well as the analysis of numerical properties of various lattice Boltzmann algorithms. Finally, it quantified the effect of pipe eccentricity and diameter ratio on the propagation of a Taylor bubble inside a water-filled annular pipe, concluding that a previously defined closure model captured the diameter ratio for the cases examined. To extend this work, future studies aim to analytically investigate the stability properties parametrically observed in this study and apply the findings to simulate the interaction of multiple Taylor bubbles.

Friction welding of dissimilar joints copper-stainless steel pipe consist of 0.06 wall thickness to pipe diameter ratio

This paper examines dissimilar friction welding between electrolytic tough pitch copper (ETP-Cu) and stainless steel (SS) of grade 304 L for pipe joint configuration, having 0.06 wall thickness to pipe diameter ratio. The welding is performed using the continuous drive friction welding method. The welded joint is evaluated by visual inspection, leak-proof ability by helium leak detection testing, microstructure features by optical and scanning electron microscopy, energy dispersive x-ray spectroscope, x-ray diffraction patterns, tensile testing, and hardness measurements. The continuity of welding is evaluated by peripheral inspection and testing on four different locations of pipe welded joint. The results revealed that sound joints between dissimilar materials of Cu-SS are established with evidence of resistance to leak at room temperature and after cryogenic shock test. The Cu-SS pipe joint received excellent strength of 242.48 N/mm2, which is nearly 80% of ETP-Cu base material. The microstructure changes are distinctly observed at the Cu side, whereas no significant microstructure changes are observed at the SS side. The microstructure features are consisting of full dynamic recrystallization zone and partial dynamic recrystallization zone that are identified at the Cu side. However, no adverse effect of microstructure on tensile strength and hardness is observed. The weld continuity in the periphery of pipe configuration is observed at four different locations. A continuous reaction layer at four investigated locations is identified, with the presence of Cu and Fe elements at the joint interface.

Thermal performance and optimization of a casing pipe solar energy storage floor with phase change material

For PCM utilization in building component, energy storage structure is expected to improve the ability to extract heat from heat source and dissipate heat to the room at the same time. This paper presents a ring-shaped energy storage structure with combination of an outer casing pipe and an inner coil pipe in heating terminal. To better understand thermal performance and integration strategy of the terminal, effects of thermal parameters of PCM and structural parameters of casing pipe are analysed by numerical model. Root mean square deviation (RMSD) are 0.3% and 2.1% with experiments conducted to validate numerical model. Compared with conventional PCM and traditional heating terminal, casing tube PCM heating terminal have highest stability coefficient index at 0.983, which shows its thermal constancy and comfort level. Results show both thermal conductivity and heat of fusion of PCM have lifting limit at 0.2 W/m2·K and 350 J/g for enhancing the heating terminal thermal performance. PCM melting temperature have matching point at 293 K for high concrete layer surface average temperature and low temperature amplitude. Changing the ratio of casing and coil pipe diameter from 1.5 to 2 could reduce 12.3 K temperature fluctuation on floor surface. The above research provides a heating terminal which can simultaneously enhance heat absorption from heat source and emission to indoor room, while a basic reference for the terminal design and selection is investigated.

Behaviour of buried continuous pipelines crossing strike-slip faults: Experimental and numerical study

The paper examines the behaviour of buried continuous pipelines crossing strike-slip faults using experimental and numerical modelling. A newly developed experiment setup is presented along with the derivation of relevant scaling laws and non-dimensional terms governing global response of continuous pipelines to strike-slip faulting. Four model tests are carried out to understand the performance of the pipelines and the results are presented through the derived non-dimensional framework. Three-dimensional (3D) Finite Element (FE) model is also undertaken to simulate buried continuous pipelines crossing strike-slip faults and is calibrated against the model test results and a field case record for validation and verification. A parametric study is also carried out to better understand the parameters influencing the response of buried continuous pipelines to strike-slip faults and to also investigate the effects of pipe end conditions on their behaviour. API 5 L X70 steel pipe with 490 MPa of yield strength was used in the numerical parametric study. Two different scenarios based on fault crossing angle of the pipe (β) were considered in the parametric study: (a) pipelines in tension and bending; (b) pipelines in compression and bending. The experimental and numerical results show that the longitudinal pipe strains under strike-slip faulting are strongly dependent on six parameters: (a) normalized fault displacements (represented by δ/D where δ is the fault displacement and D is the pipe diameter which is also an indication of soil strain in the mobilised zone); (b) ratio of pipe diameter to wall thickness (D/t); (c) fault crossing angle of the pipe (β); (d) relative soil-pipe stiffness (kD4/EI); (e) ratio of burial depth to pipe diameter (H/D) and (f) pipe end conditions. Finally, practical implications of the study are discussed.

Numerical Simulations of Turbulent Flow Through an Orifice Plate in a Pipe

Abstract Orifice flowmeters are widely used in industries to measure the flowrate in pipelines. The flowrate inside the pipe can be calculated using the relationship between the flow velocity and the pressure drop across the orifice plate. In the present study, numerical simulations have been carried out using three-dimensional Reynolds-averaged Navier–Stokes (RANS) equations combined with the k–ω shear-stress transport (SST) turbulence model to thoroughly investigate the turbulent flow through a circular square-edged orifice with various orifice plate thicknesses and orifice diameters inside a pipe at different Reynolds numbers ranging from 2500 to 40,000. The orifice thickness to pipe diameter ratio (t) varies between 0.125 and 2, and the orifice diameter to pipe diameter (β) varies between 0.25 and 0.75. The resulting centerline profiles of the streamwise velocity and pressure of the present study are compared with the previous published numerical results and experimental data as the validation study. The effects of Reynolds numbers and orifice geometries on the pressure, the flow velocity, and vorticity distribution in the orifice are discussed in detail. It is found that for the fixed β, the discharge coefficient increases with the increasing t, and the vortical structure inside the orifice is separated into two regions located at the two edges of the orifice. For the fixed t, the size of the large recirculation motions behind the plate increases, and the vorticity around the plate becomes stronger with the decreasing β.

Centrifuge modelling of pipe-soil interaction in clay with crust layer

Seabed in regions, such as the Gulf of Guinea and North West Shelf of Australia, may exhibit a crust layer where the undrained shear strength can be an order of magnitude higher than that of the immediately underlying sediment. This can complicate design of steel catenary risers, where fatigue depends on the cyclic vertical stiffness of the pipe-soil interaction. Potential punch-through of the riser into the underlying soft soil may invalidate design assumptions based on the pipe-soil stiffness within the crust layer. The long-term evolution of pipe-soil stiffness within the crust layer, which exhibits similar properties to an over-consolidated soil, is also poorly understood. This paper describes centrifuge model tests undertaken in a clay sample with a crust layer, simulating the punch-through process of a pipe under load control and investigating the pipe-soil stiffness during long-term cyclic loading tests under displacement control. Results confirm that the potential for punching-through the crust layer depends strongly on the relative ratio of pipe diameter to crust layer thickness. The long-term evolution of pipe-soil stiffness showed a steady increase after an initial remoulding stage in contractile soils (normally consolidated and lightly over-consolidated), but a steady reduction in the heavily over-consolidated, more dilatant, crust. The magnitude of pipe-soil stiffness changes (during both remoulding and reconsolidation) is governed by the over-consolidation ratio of the soil and the amplitude of the cyclic displacements. This study provides insights on the relevant cyclic stiffness to consider when assessing SCR fatigue life in over-consolidated soils and soils exhibiting a superficial crust layer.

Modelling and analysis of flow of powders through long pipelines

Purpose The purpose of this paper is to focus on predicting the pressure drop in fluidized dense phase pneumatic conveying of fine particles through pipelines by modelling the solids friction factor in terms of non-dimensional parameters using experimental data of definite pipeline configuration. Finally, the model is to be tested for a different pipeline configuration. Design/methodology/approach Solids friction factor has been expressed in terms of certain non-dimensional parameters such as density ratio, solids loading ratio and mean particle diameter to pipe diameter ratio, and a certain number of coefficients and exponents. Experimental data of five conveying materials (two types of fly ash, two types of alumina and one type of cement meal) for a pipeline configuration of diameter 53 mm and length 173 m and another conveying material EPS dust for two pipeline configurations (69-mm diameter, 168-m long; 105-mm diameter, 168-m long) have been used to calculate the unknown coefficients or exponents of the mathematical model for solids friction factor. Findings The developed model gives the best results in predicting the pressure drop for the pipelines that are less than 173-m long, but the model shows a large error for the pipelines more than 173-m long. Research limitations/implications Current research will be helpful for the researchers to model the process of pneumatic conveying through long distances. Practical implications The method will be helpful in conveying powder materials through long distances in cement or brick industry, alumina industry. Social implications Fly ash piles over at the nearby places of thermal power plants. Pneumatic conveying is the best method for transporting the fly ash from the location of power plants to the nearby brick industries or cement industries. Originality/value Solid friction factor has been presented in terms of four non-dimensional parameters and evaluated the accuracy in predicting the pressure drop for two different pipeline configurations.

Study on fluidization process in jet flow dredging device and the effects of device structure to sand collecting performance

The device structure has important influence on the sand collecting performance of jet flow dredging device. In order to study the effects of device structure, this paper presents a research for fluidization process of compact packing sand in jet flow dredging device. The calculation method which considers the cohesive strength between particles is proposed. The effects of arrangement of jet pipe and diameter ratio between jet pipe and suction pipe on sand collecting performance are studied. By comparison, we found that the structure of jet pipe inside suction pipe has better sand collecting performance than it outside suction pipe. With the jet velocity increasing, the pipe diameter ratio corresponding to the maximum concentration of particle phase at outlet reduces.

Development of closure relations for the motion of Taylor bubbles in vertical and inclined annular pipes using high-fidelity numerical modeling

This study analyses the flow of Taylor bubbles through vertical and inclined annular pipes using high-fidelity numerical modeling. A recently developed phase-field lattice Boltzmann method is employed for the investigation. This approach resolves the two-phase flow behavior by coupling the conservative Allen–Cahn equation to the Navier–Stokes hydrodynamics. This paper makes contributions in three fundamental areas relating to the flow of Taylor bubbles. First, the model is used to determine the relationship between the dimensionless parameters (Eötvös and Morton numbers) and the bubble rise velocity (Froude number). There currently exists no surrogate model for the rise of a Taylor bubble in an annular pipe that accounts for fluid properties. Instead, relations generally include the diameter of the outer and inner pipes only. This study covered Eötvös numbers between 10 and 700 and Morton numbers between 10−6 and 100. As such, the proposed correlation is applicable to concentric annular pipes within this range of parameters. An assessment of the correlation to parameters outside of this range was made; however, this was not the primary scope for the investigation. Following this, the effect of pipe inclination was introduced with the impact on rise velocity measured. A correlation between the inclination angle and the rise velocity was proposed and its performance quantified against the limited experimental data available. Finally, the high-fidelity numerical results were analyzed to provide key insights into the physical mechanisms associated with annular Taylor bubbles and the shape they form. To extend this work, future studies on the effect of pipe eccentricity, diameter ratios, and pipe fittings (e.g., elbows and risers) on the flow of Taylor bubbles will be conducted.

Unsteady turbulence structure in and downstream of a short elbow at post-critical Reynolds numbers

Unsteady turbulence structures in and downstream of a short elbow (radius to pipe diameter ratio 1.0) were studied experimentally for sub-to-post-critical Reynolds numbers (Re = 1 × 105 to 3 × 105). Measurement of the velocity field was carried out using particle image velocimetry (PIV) combined with proper orthogonal decomposition (POD) analysis. The mean velocity, turbulence intensity, power spectrum, spatial variation of POD modes, and time variation of instantaneous velocity and vorticity fields were evaluated. The experimental results indicate that a separation region forms around the elbow exit, which is almost independent of the Reynolds number for the post-critical Reynolds numbers. The power spectrum analysis indicates that the periodic oscillation is observed at Strouhal number 0.5, and that it originates from interaction of the secondary flow in the elbow and the unsteady separating flow behavior near the exit of the inner elbow wall. Furthermore, POD analysis was conducted to clarify the variation of POD modes in the elbow flow. It was found that the periodic velocity fluctuation is generated by the oscillation of the flow in spanwise direction downstream of the elbow, which consists of a secondary flow structure directed to the inner elbow wall, and a streamwise longitudinal structure along the centerline of the elbow. The POD reconstructed velocity and vorticity fields indicate periodic oscillation of the entire secondary flow arising from unsteady oscillation of a pair of vortices in the cross section of the elbow; this condition prevails in and downstream of the elbow.

Friction factor calculation for turbulent flow in annulus with temperature effects

Purpose The purpose of this paper is to present a new friction factor equation for practical use, including fluid temperature, pipe diameter ratio and inner pipe rotation effects. Design/methodology/approach A friction factor relationship is developed by applying Buckingham’s Theorem of dimensional analysis. Then, the formula is calibrated using experimental data conducted at Izmir Katip Celebi University flow loop. Moreover, the effects of fluid temperature, inner pipe rotation and pipe diameter ratio on friction factor are investigated experimentally. Findings Satisfactory agreements are obtained between proposed formula and experiments. The experimental results indicate that major variable parameters affecting friction factor is Reynolds number. Pipe rotation has negligible effect on friction factor at high Reynolds number. Prandtl number is one of the important parameters affecting the friction factor. Moreover, as the pipe diameter ratio is decreased, friction factor increases. Originality/value Determining fluid behavior of fluids under high temperature is especially important for deep wells during drilling. Temperature drastically changes fluid properties and flow characteristics in wells. These changes have a remarkable effect on pressure losses. However, since the temperature is considered constant in the calculation of the pressure loss, problems can be encountered in most systems. Friction factor is one of the important parameters for determining pressure loss in closed conduits. The originality of this work is to propose a new friction factor equation for practical use, including fluid temperature, pipe diameter ratio and inner pipe rotation effects.

An ANN‐based failure pressure prediction method for buried high‐strength pipes with stray current corrosion defect

AbstractWith continued increasing construction of both electrified facilities and buried high‐strength pipelines in China, stray current corrosion defects have become an nonignorable threat for these pipelines. A comprehensive investigation on a new failure pressure prediction model for high‐strength pipes with stray current corrosion defects was conducted in this study. The mechanism of stray current corrosion in steel pipes was firstly elaborated in brief. After that, a parameterized finite element model for stress analysis of pipes with external corrosion defects was programmed by APDL code developed by general software ANSYS. By comparing numerical results with full‐scale experimental results, both the numerical model and the failure criteria for pipe burst were proven to be reasonable. Based on the finite element model, parametric analysis was performed using a calculation matrix set by orthogonal testing method to investigate the effects of three main dimensionless factors, that is, ratio of pipe diameter to wall thickness, nondimensional corrosion defect length, and nondimensional corrosion defect depth on pipe's failure pressure. Utilizing the parametric analysis results as database, a multilayer feed‐forward artificial neural network (ANN) was developed for failure pressure prediction. By comparison with experimental burst test results and results of previous failure pressure estimation model, the ANN model results were proven to have both high accuracy and efficiency, which could be referenced in residual strength or safety assessment of high‐strength pipes with corrosion defects.

Research on optimization of dust measurement pipeline based on Bernoulli Effect

According to the principle of Bernoulli Effect in fluid mechanics, a dust measurement pipeline with Bernoulli Effect is designed. According to the previous research of the projec, this paper simulates by CFD software, obtains the particle motion velocity and electrostatic induction under different pipe diameter ratio, and finds out the maximum electrostatic induction under the better tube diameter ratio. The annular electrostatic sensor is used to find a better diameter ratio for Bernoulli Effect tube. The improved device model with different pipe diameter ratio was established in Gambit2.4, and 2D stereo model was used for experimental simulation. The velocity cloud map of particle motion is obtained by using FLUENT6.3 to solve the problem, and the corresponding velocity value is obtained according to the cloud image. The electrostatic induction calculation by MATLAB shows that when the diameter ratio d / D is 0.4 and the velocity is 9.76m/s, the electrostatic induced charge of dust particles is the largest at this time. It has certain guiding significance for the design of dust measurement pipeline.

Thermal modeling of deep borehole heat exchangers for geothermal applications in densely populated urban areas

Ground coupled heat pumps are known as very energy efficient heating and cooling systems for a variety of building applications. In densely populated areas where new urbanization is intense, deep ground heat exchangers can be a valuable and effective solution for geothermal heat pump applications. In this paper a finite difference numerical model has been developed starting from literature contributions by Holmberg et al. (2016). The in house Fortran90 code has been built and validated to cope with variable longitudinal and radial mesh distribution for simulating coaxial pipe configurations. Different ground properties and geothermal gradients can be applied. Far field boundary conditions, ground pipe meshing and Courant numbers have been varied for enhancing the accuracy in predicting the fluid temperature evolution. The model has been extensively validated against analytical solutions and literature data. The model has been applied for analyzing the behavior of deep heat exchangers in the 500–800 m range and the effects of the pipe diameter ratio have been investigated both in terms of fluid temperature evolution and pressure losses inside inner and annular pipes.

Investigation on scour protection of submarine piggyback pipeline

This paper presents the results of laboratory experiments and numerical simulations to investigate the effect of different piggyback pipeline configuration on the morphology of local seabed scour subject to steady currents. Piggyback pipeline configuration investigated includes the commonly used piggyback pipeline, namely a small pipe attached on the top of large pipe and new form of piggyback pipeline proposed in this study in which a small pipe is attached to the large pipe on the upstream and downstream side, respectively. Pressure gradient, drag coefficient, lift coefficient and scour extent around pipelines are measured and analyzed for a range of pipelines and current conditions. Results show that the vortex strength downstream of the commonly used piggyback pipeline is larger than that for a single as well as the new piggyback pipeline under the same condition. This new type piggyback pipeline can effectively reduce the depth and width of the scour hole. In particular, when the ratio of the small pipe diameter over the large pipe diameter is greater than 0.3, little scour under this new type piggyback pipeline occurs for the test conditions. The bed topography downstream of the pipe has also been altered to favor the backfill.

Optimization of ground heat exchanger using microencapsulated phase change material slurry based on tree-shaped structure

Taking into account the potential of the tree-shaped ground heat exchanger to reduce pressure losses and microencapsulated phase change material slurry to enhance heat transfer performance, a new attempt combining microencapsulated phase change material slurry with tree-shaped structure is proposed in this paper. Firstly, to obtain the optimal structure of tree-shaped ground heat exchanger, influences of structure parameters on thermo-fluidic performance of ground heat exchanger are explored. Based on this optimal structure, numerical simulations adopting Eulerian-Eulerian approach are conducted to study hydraulic and heat transfer performance of microencapsulated phase change material slurry flowing through horizontal tree-shaped structure under constant flux. Comparison studies between different working fluid: water and microencapsulated phase change material slurry and different types of tube: horizontal straight tube and Y tube (tree-shaped tube) are studied. The results indicate that the numerical results accordwellwith experimental results. For tree-shaped ground heat exchanger with bifurcation level of 1, the optimal pipe diameter ratio meets D0/D1=23/7, D1/D2=1 and the optimal length ratio is L0/L1=1. Furthermore, the combination of microencapsulated phase change material slurry and tree-shaped structure can efficiently enhance thermal performance and reduce pressure losses. Considering comprehensive performance of microencapsulated phase change material slurry, the optimal volume fraction is 12% for Y tube, whose overall performance is 38.9% higher than that of pure water flowing through straight tube.