## دانلود پایان نامه کارشناسی ارشد انگلیسی دربارۀ مطالعه عددی تشکیل قطره به روش لتیس-بولتزمن Lattice Boltzmann Method

Liquid droplets are widely used as reaction media for the chemical manipulation of cells. The droplet formation and cell encapsulation process involves multiphase flows along with coupled cell membrane-fluid mechanics. In this study, the droplet formation behavior in a T-shaped micro-fluidic device is simulated using two- and three-dimensional lattice Boltzmann method (LBM). With the adoption of pseudo potential model, the LBM can accomplish the accurate tracking of the liquid-liquid or liquid-gas interface automatically. The two-dimensional simulation results agree favorably with experimental results in the aspects of droplet length and the droplet shapes before and after the breakup. For the two-dimensional cell model, the effects of the two important dimensionless parameters, the shear rate and the reduced ratio of bending to elasticity moduli, are investigated systematically. The deformation of the cell in the process of cell encapsulation is found to have close relation with the local flow flied. Surprisingly, it is found that, the cell is still experiencing the force from the surrounding fluid even when the steady transportation of the cell has started after it has been capsulated in a droplet. In the three-dimensional simulations, three regimes of droplet formation are clearly identified as the capillary number increases from 0.002 to 0.056. The previously known four stages of squeezing regime are reproduced.

## دانلود پایان نامه انگلیسی کارشناسی ارشد دربارۀ AUV

در این پایان نامه از روابط تجربی و نرم افزار MATLAB برای محاسبه مشتقات هیدرودینامیک یک AUV استفاده شده است. متن کد MATLAB در انتهای پایان نامه آورده شده است.

## دانلود پایان نامه کارشناسی ارشد آنالیز انتروپی بعنوان وسیله ای برای بهینه کردن biorefineries

The objective of this thesis is to develop entropy analysis as a possible evaluation tool

for optimization of biorefinery processes. This is a new application of entropy

analysis which is rarely discussed in the literature. The scientific basis of the entropy

analysis is described and the proposed methodology is explained. The position of

entropy analysis among other system analysis tools such as exergy analysis and life

cycle assessment is discussed along with entropy analysis earlier applications.

## دانلود پایان نامه انگلیسی کارشناسی ارشد طراحی و آنالیز یک سیستم جذبی خنک کاری کمک شونده با انرژی خورشیدی و مجتمع با ذخیره کننده حرارت نهان

Air conditioning is one of the major consumers of electrical energy in many parts of the world.

The demand can be expected to increase because of the changing working times, increased

comfort expectations and global warming. With more air conditioning units, the electricity

demand has been rising thereby increasing the use of fossil fuels and nuclear energy. A drastic

change, therefore, should be implemented in the energy structure of the developed countries.

Environmentally friendly and energy efficient technologies should be introduced in which the

environmental impact of the conventional air conditioning system is minimized.

Solar radiation as a sustainable energy resource is one of the most available forms of energy on

the earth surface which could reduce the fossil fuel consumption and CO2 emission to the

atmosphere. Solar cooling is a possible technological alternative to conventional air

conditioning systems that has recently attracted a growing interest. A solar assisted absorption

cooling system as a sustainable solution for cooling systems could provide both heating and

cooling of a building. Since the solar energy is available for only a fraction of the day and its

availability depends on several factors such as latitude and sky clearness, the storage of it is an

important concern. Thermal energy storage is a practical way in conserving the solar energy as

it can reduce the discrepancy between the energy supply and demand. Latent heat storage units

(LHSU) using Phase Change Materials (PCMs) are promising candidates as heat storage media.

In this thesis, the behavior of a solar assisted single effect absorption system integrated with

LHSU was investigated. The mathematical model for the single effect absorption system and

the LHSU based on the mass and energy balances and heat transfer equations were developed.

The models were implemented in MATLAB and the numerical results were validated with the

experimental results from the literature. Based on the cooling demand of a specific building

(waiting room in Schiphol airport) the absorption system and the LHSU were designed and the

behavior of each system for different control parameters is investigated. For the designed single

effect absorption system, variation of the COP and the evaporator heat transfer rate at the

different flow rates and temperatures of the external cool water, hot water and the chilled water

were studied. The results show that the chilled, hot and cooled water temperatures have

significant effect on the performance of the absorption system. For the designed latent heat

storage, several numerical investigations were conducted. The impact of the key parameters e.g.

the mass of PCM, the number of tubes inside the PCM container and the radius of the tubes, on

the thermal performances of the latent heat storage and the melting time duration were studied.

The behavior of the designed latent heat storage unit in charging process with varying solar

collector field area was studied subsequently. The discharging process of LHSU for the

maximum cooling demand of the building was investigated. It was observed that the designed

LHSU could provide the requested hot water temperature for more than 10 hours which is

sufficient for driving the air conditioning system.

## دانلود پایان نامه انگلیسی کارشناسی ارشد دربارۀ Modeling of Resin Transfer Molding of Composite Materials

The goal of this research was to develop a computer model for the treatment of

Resin Transfer Molding (RTM) of unidirectional layer stranded fabrics oriented in

various directions. The individual fabric layers contain high fiber volume fraction

strands, separated by channels, which the model includes as separate phases. A finite

difference approximation has been developed to determine the effective permeability of

the channels. This approximation is based on classical channel flow equations, and is

applied to all three directions of the channels. The axial permeability in the strands has

been measured. The transverse permeabilities in the strands are assumed to be equal, and

are fitted to the model results.

The model consists of a finite difference routine which uses cell centered grids to

approximate the geometry of the reinforcement. The moving boundary resin is treated

with as constant pressure condition. The injection and vent ports are also modeled as

constant pressure conditions.

The model has been correlated with experimental results. Simulations and

experiments have been run using a single fabric layer at 0, two layers at ±45, and three

layers at 45/0/-45 and 0/±45. The model accurately captures the flow front shape for

each case, and shows general agreement with the positions vs. time