Investigating the performance and feasibility of using ram impact pumps in rural water supply systems

Master's Thesis (Civil Engineering - Water and Wastewater Engineering)

Abstract:

In this study, ram impact pump modeling has been done by the developed software. This software finds the outputs of the HAMMER software as input and by obtaining other information (including pumping height, etc.) it calculates the amount of pumped water every time the valve is suddenly turned off and on. Based on the technical and economic analysis, the above modeling shows that in cases where the pumping flow rate is low, a ram pump can be used instead of conventional pumping.

Effective factors in the modeling and design of the ram pump include the diameter of the pumping line, the time of closing and closing the valve, the volume of air in the air chamber and so on. is These parameters have been studied and analyzed in the design of this type of pump.

One of the most important advantages of the mentioned pump is not needing to use expensive energy such as fossil energy or electric energy. In cases where it is difficult and expensive to use the aforementioned energies, using a hammer pump can be useful.

Key words:

hammer pump, HAMMER software, rural water supply, hydraulic modeling

Chapter 1

Introduction of the research

1- Introduction of the research

Pumps [1] are one of the main components of the water supply industry. This unit is considered as a strategic facility and is one of the main items of energy consumption in the water supply system. In order to define this thesis more fully and accurately, first a brief discussion about the types of pumps and their grouping in terms of energy use (direct use or indirect use) seems necessary.   

Based on how energy is transferred from the pump to the fluid, pumps are divided into three general categories (Noorbakhsh, 2015):

Dynamic pumps[2]

Positive displacement pumps[3]

Special pumps[4]

Dynamic pumps are pumps that increase the kinetic energy of water. In this type of pumps, the energy transfer from the pump to the fluid is carried out continuously, and the amount of fluid passing through the unit of time (watering) and the fluid output pressure from the pump are interdependent. This category of pumps includes a completely diverse subcategory, of which wheel pumps [5] are the most important of them, which are divided into three categories based on the path of fluid movement in the wheel: radial pumps [6] (to create high pressure and relatively less flow), axial pumps [7] (to create high flow and lower pressure) and mixed pumps [8] (to create medium pressure and flow) (Noorbakhsh, 1385).

In positive displacement pumps, the transfer of energy to the fluid takes place intermittently. These pumps are divided into different types, the most important of which are reciprocating (piston) [9], circulating [10] and tubular [11] pumps. These types of pumps are usually used for unusual flows and viscosities and are often used in industry (Noorbakhsh, 2015).

Other pumps that have a different mechanism from the two categories of pumps mentioned are in the category of special pumps. These types of pumps include air pumps [12], ejector pumps [13] and ram pumps [14]. In these pumps, the way of transferring energy to the fluid to perform a certain movement is slightly different from the first two types. But again, they can be included in the first two categories.

The ram pumps, which are the subject of this thesis, are among special pumps, but they can also be classified as positive displacement pumps. In these pumps, the energy of the unstable ram impact [15] in a water supply line is used to transfer water to a high height but in limited flow rates. The feasibility of using this type of pumping in water supply projects in remote areas and with high altitude differences is the subject of research in this thesis. 1-1- The purpose of the project and the necessity of doing it Considering the high cost of conventional energy supply (including electric energy or fossil energy) in the use of common pumps in the water industry, the use of pumps that have a simpler mechanism and less energy consumption can be attractive. be suitable Water ram pumps only use hydraulic energy caused by unsteady flow [16] in pipelines to pump water.Water ram pumps only use hydraulic energy caused by unsteady flow [16] in pipelines to pump water and do not need to use electrical or fossil energy. Also, in some rural areas, due to special topographical conditions, supplying water to neighboring villages through a pumping station (water supply complexes) is difficult and expensive. The use of ram pumps can be considered as one of the options to solve the above problems. 1-1-1- Main objectives The main objective of this thesis is the feasibility of implementing such pumping stations in water supply systems, especially in rural areas. 1-1-2 Sub-objectives

Among the other objectives of the project, the following can be mentioned:

Preparation of a software program to facilitate and optimize the design of ram pumping stations

Determining the technical and economic limits of using this type of pumping

Protecting the main water transmission line against the pressures caused by ram impact (in addition to water pumping)

1-2- Hypothesis Main

The main assumption of the research is that if ram pumps are used in the villages where this project is possible, it is possible to transfer water to the mentioned villages with high efficiency and an acceptable cost-benefit ratio without using expensive electric or fossil energy. In this project, by comparing the technical and economic implementation of a plan in two cases of conventional pumping stations or the use of water ram pumps, in order to prove the above hypothesis. and effective mechanisms)

Study of the existing situation of rural water supply systems in Ardabil province and the feasibility of using hammer pumps in them

Choosing one of the existing designs as a pilot plan

Modeling the selected design using existing software

Designing the pumping system by hammer hammer in the desired station

Modeling the prepared plan and determining the coefficients The resistance and diameter of the pipes and the design of the required equipment

summarizing the results and comparing it with the conventional methods of pumping stations from a technical and economic point of view

concluding and presenting suggestions

drafting the thesis

1-4- The structure of this report

This report consists of the following 5 chapters:

Chapter one: The generalities, objectives and necessity of research

Chapter two: Impact pump

Chapter three: Research materials and methods

Chapter four: Research results and analysis of results

Chapter five: Conclusion and suggestions

Chapter two

Impact pump

2- Impact pump

As stated in the first chapter, the impact pump is one of the special pumps. In this chapter, firstly, the ram impact phenomenon and the basic equations in this field are introduced, and then the software available in the field of analysis of the above phenomenon are briefly introduced. In the end, the history of the ram pump and the pumping mechanism in this type of pump are examined. 2-1- Ram phenomenon in water transmission line systems In hydraulic systems under pressure, such as water transmission lines, oil or distribution networks and water pipes leading to turbines, water tunnels, pumping systems and gravity flows, there is a possibility of unstable flow. which, by creating fast and fleeting and damping waves, causes various risks such as failure and breaking of valves, control valves, pumps, pipelines and so on. It can be called a battering ram. Ram shock is a phenomenon whose effects can be compared to electrical and mechanical waves in systems under pressure, and therefore it can be compared and analyzed using common laws. In fact, the ram impact mechanism shows the sensitivity of a fluid transmission system to any change in flow rate, speed and flow pressure. The ram impact that occurs as a result of changes in flow rate or speed creates a certain amount of force that moves upstream or downstream in the form of a wave with a constant speed in the flow pipeline (the analysis of the ram impact is based on the principle of conservation of momentum).