Using a kind of mixed-flow pump as the object of the study,the time-averaged continuity equation with relative coordinates and the N-S equation are established on the basis of FLUENT software,and the numerical simulation was made by using standard k-ε equation with turbulence model,unstructured tetrahedral network and SIMPLE algorithm .On the basis of the irrelevance of grid number, the static pressure and absolute velocity distributions of impeller blades and stator blades were calculated.And the water resistance coefficient simulation when it is static and the performance parameter simulation when it is rotary were made under different number of stator blades and different inlet angle of stator blade. When the number of impeller blades is 4 and other parameters remain unchanged ,the water resistance coefficient is lowest when the stator blades number is 3, and the head and the efficiency are highest when the stator blades number is 9.When other parameters do not change, the inlet angle of stator blade are +2.5°、0°、-2.5°, the water resistance coefficient was lowest 、 the head and the efficiency are highest when the inlet angle of stator blade is 0°,and the water resistance coefficient,the head and the efficiency don't change significantly.The results show that under special environment the number of stator blades should be taken less to obtain lower water resistance coefficient when the requirements of the design efficiency were insured,and when designing space diffuser to obtain lower water resistance coefficient ,the mixed- flow pump performance have no significant change when the inlet angle of stator blade changed in the range of about 5°.

A commercial kitchen is a complicated environment including multiple components, such as hood exhaust, conditioned air supply, and makeup air systems，which work together but not always in unison. The main object is to investigate the difference between mixing and displacement ventilation through numerical simulation using a validated Computational Fluid Dynamics (CFD) model. The comparison was reported in thermal comfort and indoor air quality. It shows that using thermal displacement ventilation in kitchen allows for a reduction in space temperature without increasing the air-conditioning system capacity and through proper design, displacement ventilation (DV) can maintain a thermally comfortable environment that has a low air velocity, a small temperature difference between the head and ankle level, and a low percentage of dissatisfied people, and provide better IAQ in the occupied zone.

A compound insulation plastic board of filled corn rod broken powder the polyurethane foam was invented, preliminary to decide its formula and preparation technology, according to the test results of different corn rod broken powder size (0 ~ 0.45 mm and 0.45 ~ 1.5 mm and 1.5 ~ 4 mm three kinds of specifications) and filling quantity of polyurethane foam plastics density, compression strength and thermal conductivity, and the influence of the different filling quantity and grain size of polyurethane foam plastic foam time, foam molding effect. The results show that as the corn stalk broken powder particle size must, along with the increase of filling quantity, filling, corn stalk broken powder of polyurethane foam insulation material density and the increase, but the compression strength drops, when corn rod broken powder particle size of 0.45 ~ 1.5 mm, filling content is 30%, the preparation of complex polyurethane foam plastic board compression strength (compression 50%) for 185 kPa, heat conduction coefficient is 0.038 W/m • K, variation of size (－40 ~＋ 70 ℃) for plus or minus 1%, can satisfy the channel lining seepage control project for expansion in the performance requirements of destruction. According to the calculation and don't fill corn rod broken powder of polyurethane foam plastic board compared, the hybrid foam insulation board can reduce the cost of about 25%, and be able to make full use of agricultural production waste, reduce the waste away or burned the environmental pollution.

 In order to study the nonlinear dynamics characters of hydro-turbine governing system with a complex pipe system, a nonlinear model of hydro-turbine governing system was established where one considered the nonlinearity of transfer coefficient with the hydro-turbine governing system work conditions changing. Based on nonlinear dynamics theory, the nonlinear dynamic behavior of hydro-turbine governing system was analyzed including bifurcation diagrams, Poincare maps, power spectrum diagram, time domain diagram, phase orbits diagram and spectrum diagram. Furthermore, numerical simulations were carried out， it shows that the law between the rotation speed of hydraulic turbine and watergate opening degree was discovered when the parameters of hydro-turbine governing system are varying. And the parameters range of the hydro-turbine governing system which can ensure the system work in stable condition was got. The results show that when governor parameters varying in the stable area of system response bifurcation diagrams, the system work in a stable condition, while, if governor parameters exceed the area ,the output of hydro-turbine governing systems appears constant amplitude, divergence, and even chaos. Therefore, all of these results provide the theoretical basis for the system working well.

In order to explore the pump chamber initial volume influence on the performance of piezoelectric pump, the check-valved double-chamber piezoelectric pumps in parallel with six different initial pump chamber volumes were designed and manufactured . When powered by 110V drive voltage, within operating frequency range of less than 400Hz, the output performance experiments under different compression ratios were carried out with water and air as the medium respectively. The results showed that the compression ratio(The ratio between the stroke volume and the initial volume defines the compression) of 1 / 18 of pump output flow rate was the best when pumping liquid water, the maximum output flow was 1330 ml/min .While the larger compression ratio was , the better the pump output pressure and self-priming capability were. The maximum self-priming water column height and output pressure were 69 cm and 58.5 kPa respectively . When pumping gas air, the larger the compression ratio was, the better the pump output capability was. The maximum output flow-rate and output pressure was 850 ml/min and 6.5 kPa respectively. When the compression ratio was less than   1 / 32, the pump had lost output capability.

The RNG k-ε turbulence model, Euler-Lagrange multiphase flow model were applied to simulate the water flow and movement of sediment in a prototype double suction centrifugal pump based on ANSYS FLUENT software. The influence length and location of back-blades on the concentration of sediment and efficiency of pump was analyzed. The results show: with the decrease of length of the back-blade, the decline of the pump efficiency is decreased; a minimum length of the back-blade is needed to prevent the impeller ring from sand erosion; reduce the number of from four to three is also effective in protecting the impeller ring and keep a reasonable pump efficiency; in this simulation, case 7 is the most effective.

In order to get the accurate liquid film thickness of the upstream pumping mechanical seal, the model of 3-D flow in upstream pumping mechanical seals with spiral grooves was made by Pro/E wildfire. To construct parametric micro-gap geometrical model of seal faces, using dynamic mesh technology, Fluent software was applied to simulate the flow field of spiral groove upstream pumping mechanical seal in consider of the cavitations. Liquid membrane thicknesses of different working conditions were obtained and compared with the experiments to verify the correctness of the simulation results. And the effect of working condition parameters on liquid membrane stiffness and the leakage were calculated and analyzed. Research shows that: Liquid membrane thicknesses obtained by simulation is basically in line with that of the experiments (the maximum relative error is 19.6%, the minimum relative error is 0, the average relative error is 8%), which verifies the dynamic mesh technique to the flow field simulation on the mechanical seal is feasible. the problem of cavitations should be considered in flow field calculation on the mechanical seal to obtain the true flow field characteristics the simulation based on dynamic mesh and cavitations model in the flow field can be used to predict liquid membrane thickness. Leakage and liquid film rigidity increase with the speed, medium pressure increases, and spiral groove end can produce pumping effect, meanwhile, the dynamic pressure effect are obtained.

In order to realize water-saving, good quality and high yield of tomato in southern china, the influence of irrigation and drainage mode on character of water demand and fruit yield under the condition of rain-shelter was studied. The results showed that deficit irrigation decreased soil water content over time, the treatments with drainage depth of 0.8m reduced soil water content more quickly than that with drainage depth of 0.6m, but the decline was not very obvious. The water demand of tomato was quite different at three growth stages, the order was as follows: blossom and fruit period > fruit mature and harvest period > seedling period, along with the growth of tomato, daily water requirement is rising up in the trend. Under the condition of different irrigation and drainage mode and rain-shelter cultivation, the range of daily water requirement of tomato at seeding stage was 1.07～2.71mm/d, and 1.60～3.09 mm/d at blossom and fruit period, 1.78～3.35 mm/d at fruit mature and harvest period. Deficit irrigation can reduced tomato fruit yield, but increase water use efficiency and irrigation water use efficiency at the same drainage depth of underground pipe. The research can be used for the selection of irrigation and drainage mode so as to realize water-saving, good quality and high yield of tomato under rain-shelter cultivation.

In order to investigate the nitrogen removal performance and how it response to low carbon-to-nitrogen in eco-ditch and wetland system under controlled irrigation and drainage. Based on field experiment data, the changes of nitrogen concentration and carbon-to-nitrogen in the eco-ditch and wetland system were monitored. Results showed that TN、NH4+-N and NO3-_N concentration in drainage were peaking after fertilization and then were significantly reduced after retaining in the eco-ditch. The eco-ditch obtained 63.9% TN, 67.8% NH4+-N and 83.2% NO3-_N removal. Nitrogen concentration reduced further after purification in wetland, with the average removal rate of 47.7%、44.3% and 82.0% for TN, NH4+-N and NO3-_N. The influence of organic matter in the system on water quality is little, the carbon-to-nitrogen ratio maintained low. The eco-ditch and wetland system under controlled irrigation and drainage are effective in removing nitrogen in paddy field drainage, and the influence of low carbon-to-nitrogen on nitrogen removal efficiencies is little.

Synchronous Driving Linear Move Irrigator can irrigate in variable rate by change driving speed. To improve the irrigation effect, studied water distribution information in both longitudinal and transverse directions while the linear move irrigator was drove synchronously ahead with different control method. With three-dimensional models and particle system, together with water distribution and water flow trace, three-dimensional dynamic model of water flow was built. Studied irrigation uniformity in longitudinal direction in different speed, analyzed the effect of sprinkler space and height to lateral irrigation uniformity, and optimized the configuration of sprinklers. Simulation results and field tests showed that: change the frequency of the drive motor can achieve vertical variable irrigation in driving direction, landscape direction irrigation uniformity depend on type and pressure of sprinkler. The maximum relative error between field and simulation of 3.39% shows that the simulation can reflex filed test. This study provides methods for linear move irrigator optimizing irrigation effect.

In nature, the water quality deterioration phenomenon of river, the Yangtze River, lakes, estuaries and port bay has become a highlight problem of water environment to our country. In the comprehensive management of water pollution of the environment, the hydrodynamic and water quality of movement, migration need to be mastered to predict and control the pollution. Therefore, it is quite important to establishment the hydrodynamic mode in arbitrary curve coordinate. This paper uses the boundary curve fitting method to simulate the natural river channel for the complex boundary, and to simulate the shallow water equations and the   equations which are closed and linked simultaneously. A numerical method, ADI difference scheme, is used to discrete the equations, numerical calculating 2D shallow water equations in curvilinear coordinates. Take the De Vriend’s 1800 plane curve flume experiment model as example, the numerical simulation results in this paper is validated with the experimental results of De Vriend, which is quite satisfactory. This proves that the numerical method established in this paper are reliable and correct, and it will provide reasonable and feasible means of calculation for Natural River hydrodynamic with arbitrarily complex boundary.

 In order to solve the problem of the low-frequency pressure pulsation of large Francis turbine draft tube caused by spiral vortex rope at part load operation, a simple and effective method which can weaken the vortex rope, called hydraulic disturbance, was introduced. Using the model test method, a structure for hydraulic disturbance was designed on a model turbine, and pressure fluctuation tests with hydraulic disturbance and without were carried on. The pressure pulsation amplitude and frequency characteristics at different part loads were analyzed, and the mitigation effect of pressure fluctuation with hydraulic disturbance method was studied. Studies have shown that without hydraulic disturbance there is a vortex rope in the draft tube, whose frequency is about 1/5 rotating frequency, which causes strong low frequency pressure fluctuation near the wall of draft tube, and this low frequency pressure fluctuation is the main reason for the unsteady operation of the turbine. While with hydraulic disturbance the amplitude of the low frequency pressure fluctuation is significantly reduced, but the frequency of pressure fluctuation is not changed obviously. A new way of reducing pressure fluctuation in the draft tube is presented, by which the operation stability of Francis turbine can be improved.

Temperature Analogy Method (TAM) is a new dynamic grids method using temperature analogy. Its rotation deformability was researched in this paper. For dynamic grids methods, their rotation deformability depends on their transfer modes of rotary deformation. First, taking rotating cylinders with different sizes as examples, the transfer modes of rotation deformability for TAM, spring analogy and elasticity approach were compared. Spring analogy and elasticity approach are two most popular dynamic grids methods nowadays. The analysis shows that spring analogy and elasticity approach decompose rotation around an axis into the translation along the axis. So they transfer false rotation deformation, which makes grids deformation aggregate around moving boundaries and grids around moving boundaries are distorted seriously and even staggered. However, TAM introduces rotation map to transfer the rotation of moving boundaries correctly and effectively within the whole computational domains, which avoids the false rotation deformation transfer. Second, TAM and spring analogy were used to generate dynamic grids of airfoil rotation separately. The results show that the dynamic grids generated by TAM are of good quality even for the airfoil with large scale rotation. But the dynamic grids generated by spring analogy are easy to be distorted near the moving boundaries of the airfoil. Above work indicates TAM is of greater advantages in rotation deformability.

Analyzed the impact factor of the self-cleaning screen filter's drainage flow, found that the filter drainage flow Qp is determined by the flow coefficientμ. In order to investigate the drainage flow coefficient variation, mainly conducted the sand suction opening size's impact on the flow coefficient of the self-cleaning screen filter drainage system, found that the flow coefficient increases with the sand suction relative inflow area's increase, but when the relative inflow area increases to a certain extent, the flow coefficient doesn’t change and tends to a constant. Established the drainage flow coefficient formula, analyzed the drainage flow coefficient formula and found that: when bl/A2>0.15,that is when the sand suction entrance length l>500mm(The sand suction entrance width b=300mm ,is a constant ),the sand suction opening area has less than 0.5% impact on drainage flow, the drainage coefficient hardly changes with the sand suction opening area’s increase, this variation is con-sistent with the test analysis results. According to the drainage flow coefficient for-mula, established the self-cleaning screen filter drainage flow calculation formula, conducted the mean square deviation ERMS inspection of the formula, obtained ERMS=0.00174,showed that the formula has a high fitness.

To reduce total stress, make even stress distributing and improve design efficiency of annular U-diaphragm in hydraulic diaphragm pump, the U-diaphragm stress-strain was researched and structure was optimized by Finite Element and parameter optimization method. Diaphragm model stress distributing drawing was analyzed under different compression and stretch loads in operating space and stress distributing rule was summarized by nonlinear analysis function of finite element analysis software ANSYS. The structure of fixed, moved supported end and free semicircular transitional end were optimized based on stress distributing rule. Take diaphragm maximal stress as state limited variable and unit stress summation as objective function, parameters were calculated by parameter optimization law of ANSYS. Finite Element analysis result indicates the optimal annular U-diaphragm total stress is lower and inner and outer surface sideline stress distributing is more even to avoid stress concentration problem. It provides a kind of new structure optimization design method of diaphragm based on parameter optimization which has lower pre-investment and shorter developing circle than current trial-manufacture method.

 To research the character of the high flow area at turbine mode of the pump turbine, a hydraulic model was established based on a pumped storage station. The SST k- model and two kinds of grids were used to simulate the internal flow fields and the results of the two kinds of grids were compared with the test data .The results show that in the high flow area, there are periodical distribution vortexes in the runner’s flow passages with the increase of relative speed between the liquid and runner .The vortexes increase the energy loss and at the same time, the high speed of the liquid makes high quality grids necessary for simulation, and this is the reason why the high flow area is difficult to simulate. These conclusions can provide a theory basis for the analysis and simulation of the high flow area.

When centrifugal pump runs deviated from the design condition, it will increase energy consumption but reduce the efficiency. To optimize the running condition, according to the basic theory of turbomachinery design and inlet guide vanes prewhirl regulation, two different airfoils inlet guide vanes of prewhirl device were designed. Positive prewhirl guide vanes with different airfoils have been studied to determine their hydrodynamic effect on centrifugal pumps. The result shows a single-suction centrifugal pump, appropriate design of positive prewhirl could increase the efficiency of centrifugal pumps. Compared with the performance of the centrifugal pump without inlet guide vane, the efficiency of straight blade-type centrifugal pump could mostly increase 2.05% and the reduction in power consumption could reach the maximum of 6.35%. For Gottingen bowed blade-type, the efficiency of centrifugal pump could mostly increase 2.34% and the reduction in power con-sumption could reach the maximum of 6.53%. Both types have little influence on the head. For straight blade-type, the best efficiency point changed then obtained at Q=172 m3/h. For Gottingen bowed blade-type with 20° prewhirl, the best efficiency point changed then obtained at Q=172 m3/h. Besides the best efficiency point will obtained at Q=190 m3/h when its prewhirl was 40°. The high efficiency scopes of both prewhirl were extended.

 By the energy balance theorem，The energy loss pressure ratio’s expression formula of the main flowing unit of pulsed liquid-gas jet pump was deduced, the main factors which influenced the energy conversion were analyzed, The influence of energy losses in the flow passage on the pump’s performance was studied，and the experimental and numerical study were conducted．Research was showed that the optimal area ratio of liquid - gas jet pump should be a better pressure in the larger flow interval, the m = 4.34 is the optimal area ratio through the five area - ratio experiment. Results show that the theoretical calculations agree with the measurements. The energy loss ratios of flowing units were calculated, and analyzed the relationship with the area ratio and the flow ratio. Frequency pulse jet, the jet pump area ratio, the flow ratio and the jet pump piping length is the main factor to affect energy balance and liquid-gas jet pump energy characteristics of the jet pump. Through comparing the experimental data of the pulsed with the experimental data of the steady liquid-gas jet pump in different area ratio and that pulsed jet is an effective way to enhance the liquid-gas jet pump’s efficiency．

In order to improve hydrodynamic performance of mixed-flow pump, numerical research on some factors influencing hydrodynamic performance of mixed-flow pump were carried out. The factors were the tip clearance, the rotor blade number, the rotor blade angle, the roughness, the rotor blade thickness. Internal flow field of mixed-flow pump, which was meshed by structured grids, was simulated at multi conditions by solving Reynolds-Averaged Navier-Stokes equations and shear stress transport turbulence model with multiple-reference- frame approach. The results show that the head, power and efficiency all decline with the tip clearance enhancing. The maximum efficiency can be elevated and the high efficiency zone can be enlarged by adjusting the rotor blade angle. The head and power increase with the rotor blade number increasing, but the head increasing amplitude is gradually smaller with the rotor blade number increasing. It's unfavorable as the rotor blade number too many or too few. The efficiency declines significantly with the roughness increasing. When the rotor blade become thinner, the maximum efficiency point moves to a little larger mass-flow-rate point, and a slightly increased efficiency value was gained. On premise of satisfying produce and installation requirements, optimal choices of these factors can greatly improve hydrodynamic performance of mixed-flow pump.

The flat-walled diffuser/nozzle are divided into two groups by flow resistance characteristic: the typeⅠtube and the type Ⅱ tube which has low resistance in the dispersal direction and the contraction direction relatively. The tube with the narrowest wide is 150?m, the depth 150?m is studied, and curves of ratio of two flow resistances in two directions versus cone angle ?  and length-width ratio l/w at Reynolds numbers range of 100-2000 are received. Analysis results shows that ? is dependent on ? and l/w significant when ? is small, and flow resistance transition occurs with certain ? and l/w. The trends of ? varying with ? and l/w are different at Re=100 and Re≥500 obviously. When the Re=100, most of tubes present the typeⅠtube characteristics, and ? reaches the max 1.22 when ? =20°and l/w=20. When Re≥500, most of tubes present the typeⅡtube characteristics, and ? reaches the min 0.63b when ? =20°and l/w=1.The results show that the flow resistances of flat-wall diffuser under different Reynolds number differ greatly. In order to improve the performance of pump, the appropriate structural parameters should be chosen according to the actual working condition when designing.

 In order to improve the bad condition of circulating cooling water systems such as low efficiency and high energy waste due to incorrect pump selection, unreasonable working condition regulation, unscientific operating management and hard energy consumption evaluation. A chemical circulating water system was taken for object with the procedures as spot investigation on the parameters of equipment installation and the working conditions of the pump station, compared it with the working condition under variable frequency speed regulation and found out the energy saving potential then the energy consumption and evaluation of the whole system was finished. A water supply strategy on energy-saving operation of the circulating water system was established based on the pump affinity low and was combined with components and the whole system. The strategy can meet the process demand and implement the constant pressure water supply at the most adverse point. A method of energy consumption evaluation based on the pump performance curves, motor load curves and data collected was also summarized. After the chemical circulating water system was reconstructed, the annual electric power consumption was reduced from 2.1×104 kWh to 1.4×104kWh, the power-saving proportion was nearly 33% according to the result of energy consumption monitoring.

Large eddy simulation (LES) is used for numerical simulation of 3d liquid-solid two- phase flow in jet pump. The mixture model is adopted to treat the liquid-solid two-phase interaction. The influences of solid-phase initial volume fraction and granular diameter and flow ratio on jet pump’s characteristics are analyzed. The results show that the lifting capacity and efficiency of jet pump decrease with the increase of granule density. When the initial volume fraction of sand is 10%, the pressure ratio and efficiency of the pump decrease 28.8% and 31.6% respectively compared with that of delivering pure water. With 20% initial volume fraction, the pressure ratio and efficiency decrease 39.0% and 42.2%. After fully mixing, the volume fraction of sand increases with the flow ratio because of the increase of solid-phase portion. As the granular diameter gets greater, the granules become more prone to concentration locally. As the granular diameter gets smaller, variation of internal concentration distribution curve of jet pump becomes flatter. Research results lay a foundation for engineering application.

Sealing problems in the traditional centrifugal pump could be solved by using canned pump droved by the bearingless permanent magnet slice motor (BPMSM)．Firstly, structure of centrifugal pump droved by the BPMSM was discussed and operating principle was introduced, then theoretical formulas of driving system and radial suspension forces were deduced．An experimental platform hardware and software of digital control system with TMS320F2812 DSP were designed to meet the need and the human-computer interaction interface based on the BPMSM control system for real-time online debugging and control was designed, then the experiment was performed. The results show that the controller parameters can be conformed quickly by using human-computer interaction interface, the vibration amplitude in radical direction is less than 80μm while rotor speed is changed from 0 to 2000r/min continuously under no load, the BPMSM pump and digital control system have fine static and dynamic performance, a new way is provided for liquid transmission without mechanical friction and pollution．

The operating conditions of TS65-40-125 type centrifugal pump with medium-high specific speed are changing frequently. The performances of pump, especially pressure head and efficiency, were designed to satisfy five operation conditions according to the industry demands. After analyzing the defects of prototype pump, three impellers were designed based on the enlarged flow design method. The distributions of pressure, turbulence kinetic energy, velocity in three impellers were predicted with the commercial CFX. One impeller was selected as optimal schemes and produced for experiments. The test results show that the pressure head of the new product is 5 m higher than prototype pump at the new design working condition. The efficiencies of five operating conditions are significantly improved, meeting the design requirement. Both simulating and test results show that enlarged flow design method is effective to improve the pressure head of centrifugal pump with medium-high specific speed and widen the pump high efficiency area. A reference is provided for optimal design of medium-high specific speed centrifugal pump.