Rapid design method for floating body system of oscillating water column type wave energy device

Abstract

The invention relates to a quick design method for a floating body system of an oscillating water column type wave energy device, which comprises the following steps of: selecting a proper turbine system type according to wave characteristics of a target sea area, and determining the size, blade shape and rotating speed of the turbine system; performance parameters of the turbine system are obtained through numerical simulation and experimental testing, and the performance parameters of the turbine system are simplified; according to the performance parameters of the simplified turbine system, a correlation model of the turbine system and a floating body system is established, and wave boundary conditions are set; carrying out grid division on a flow field around the floating body system, selecting a proper turbulence model and a solver, and carrying out steady-state or transient-state simulation; and calculating the primary energy conversion efficiency of the floating body system and optimizing the floating body system. According to the method, the design period and the repeated modification frequency are reduced, parameter matching between the turbine system and the floating body system is more reasonable through the whole design method, the energy conversion efficiency of the whole device is improved, and the performance of the whole system is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of wave energy conversion, and in particular to a method for quickly designing a floating system of an oscillating water column type wave energy device. Background Art

[0002] The oscillating water column wave energy device is a common wave energy conversion device, which mainly consists of a floating system and a turbine system.

[0003] The traditional design approach typically involves first designing the float system, then designing the turbine system based on parameters such as the calculated pressure value of the float. When designing the float system, the aperture size is generally determined by the porosity ratio to achieve a high primary energy conversion efficiency for the float. However, this approach, in pursuit of high conversion efficiency, often results in overly small apertures, which mismatch the aperture size of the subsequent turbine system and render the turbine system inoperable. Designing the float aperture based on the actual turbine aperture ignores the turbine's obstruction to air flow, resulting in a low and inaccurate calculated primary energy conversion efficiency that fails to truly reflect the performance of the entire system. This indicates that traditional design methods can lead to long design cycles due to repeated aperture adjustments, accompanied by relatively poor system compatibility. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for quickly designing a floating system of an oscillating water column wave energy device to solve the above problems.

[0005] The present invention provides the following technical solutions:

[0006] A rapid design method for a floating system of an oscillating water column wave energy device comprises the following steps:

[0007] Step S1, selecting a suitable turbine system type and determining the size, blade shape, and rotational speed of the turbine system according to the wave characteristics of the target sea area;

[0008] Step S2, obtaining the performance parameters of the turbine system through numerical simulation and experimental testing, and simplifying the performance parameters of the turbine system;

[0009] Step S3: Based on the simplified performance parameters of the turbine system, a correlation model between the turbine system and the floating body system is established, and wave boundary conditions are set; the flow field around the floating body system is meshed, and an appropriate turbulence model and solver are selected to perform steady-state or transient simulation;

[0010] Step S4: Calculate the primary energy conversion efficiency of the floating system and optimize the floating system.

[0011] Further, turbine system types include Welsh turbines and bidirectional turbines.

[0012] Furthermore, the numerical simulation and experimental test are to produce a scaled-down turbine system model according to the actual size and operating environment of the turbine system, and to carry out pressure drop experiments under different operating conditions of the turbine system.

[0013] Furthermore, the performance parameters of the turbine system obtained through numerical simulation and experimental testing include speed and flow rate.

[0014] Furthermore, the simplified performance parameters of the turbine system include flow coefficient, pressure drop coefficient, and resistance model.

[0015] The present invention has the following beneficial technical effects:

[0016] By first designing the turbine system and then applying the simplified parameters of the turbine system to the design of the air chamber openings of the floating body system, this invention reduces the design cycle and the number of revisions, thereby improving work efficiency. By simplifying the complex performance parameters of the turbine system into key parameters such as the flow coefficient, pressure drop coefficient, and resistance model, the design of the floating body system is more concise and clear, reducing complexity and the probability of error during the design process.

[0017] By simplifying parameters and optimizing system matching, this invention enables the floating system and turbine system to achieve a more stable dynamic response under wave action, reducing vibration and impact caused by system mismatch, thereby enhancing the operational stability of the entire device. This design approach further optimizes the parameter matching between the turbine and floating systems, improving the energy conversion efficiency of the entire device and optimizing overall system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a method for quickly designing a floating system of an oscillating water column wave energy device according to the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Example

[0021] A rapid design method for a floating system of an oscillating water column wave energy device comprises the following steps:

[0022] Step S1, turbine system selection and design, selects the appropriate turbine system type according to the wave characteristics of the target sea area, and determines the parameters such as the turbine system size, blade shape, and rotation speed.

[0023] In this embodiment, the turbine system types include Welsh turbines and bidirectional turbines; in wave energy power generation devices, the selection of turbine type requires comprehensive consideration of multiple factors. The Welsh turbine has a simple structure, low cost, and self-rectifying characteristics. It is suitable for oscillating water column devices with stable wave conditions, but has poor starting performance and high noise. Bidirectional turbines (such as impact turbines) are highly efficient and adaptable, and are suitable for complex wave environments, but have complex structures and high costs. Wave conditions, device type, cost, maintenance, etc. should be considered when making a selection. For example, small and medium-sized devices with stable wave conditions and cost-sensitive devices can choose Welsh turbines; large-scale devices with complex waves and the pursuit of high efficiency can consider bidirectional turbines or dual-turbine systems.

[0024] Specifically, based on the initial requirements, the size, blade shape, speed and other parameters of the turbine system are determined, and computational fluid dynamics (CFD) software is used to simulate the flow characteristics of the turbine under different operating conditions, optimize the blade shape, speed and other parameters, and make the turbine system more efficient.

[0025] Step S2: Obtain the performance parameters of the turbine system through numerical simulation and experimental testing, and simplify the performance parameters of the turbine system.

[0026] In this example, pressure drop experiments under different turbine system operating conditions are conducted. First, a test bench is constructed. Based on the actual turbine size and operating environment, a scaled-down turbine model is fabricated and mounted on the bench. The drive system (in this example, the motor) is connected. The intake and exhaust ducts are also arranged, and pressure sensors are installed at key locations to measure the inlet and outlet pressures. The sensors are then connected to a data acquisition system. Key measurement points are then strategically located. In this example, the sensors are installed in the straight pipe sections immediately before the turbine inlet and after the outlet to ensure that the measured data accurately reflects the pressure drop. The drive motor is then started to simulate turbine operation under different operating conditions. Different speed conditions are simulated by varying the drive motor speed, and different flow conditions are simulated by adjusting the intake valve opening. Under each operating condition, the system is allowed to operate stably for a period of time. Once the system reaches a stable state, inlet and outlet pressure data are acquired through the data acquisition system, and detailed numerical information on the corresponding operating parameters, such as speed and flow rate, is recorded. Finally, the acquired data is processed and analyzed to plot the relationship between pressure drop and operating parameters (including flow-pressure characteristics and efficiency curves), and their variations are analyzed. Furthermore, by simplifying the obtained performance parameters, the simplified performance parameters of the turbine system include flow coefficient, pressure drop coefficient, and resistance model, so as to understand the pressure drop performance of the turbine under different working conditions. In this embodiment, the flow coefficient is expressed as the ratio of the turbine inlet and outlet flow to the floating body opening area; the pressure drop coefficient is expressed as the turbine inlet and outlet pressure difference curve; the resistance model is used to describe the resistance characteristics of the turbine to the air flow, which is similar to the effect of a damper; (in other embodiments, the relevant parameters can be specific values, or related functions or fitting curves). In other embodiments, after numerical simulation and experimental testing, the pressure data of the turbine inlet and outlet are extracted, and the pressure drop value is obtained by the calculation formula. The change law of the pressure drop under different working conditions is analyzed, and the main factors affecting the pressure drop can be explored, providing a theoretical basis for the design optimization and performance improvement of the turbine.

[0027] Step S3: Based on the simplified performance parameters of the turbine system, establish a correlation model between the turbine system and the floating system, and set wave boundary conditions; mesh the flow field around the floating system, select an appropriate turbulence model and solver, and perform steady-state or transient simulation:

[0028] (1) CFD simulation settings: In the CFD software, a geometric model of the floating system is established, wave boundary conditions are set, and simplified turbine parameters are added at the opening position of the air chamber of the floating system.

[0029] (2) Meshing and solving: Mesh the flow field around the floating body, select the appropriate turbulence model and solver, and perform steady-state or transient simulation.

[0030] Specifically, a three-dimensional model is established based on the actual structure and precise geometric dimensions of the turbine system, and boundary conditions are set. According to different operating conditions, conditions such as pressure, flow rate or velocity at the turbine system inlet, as well as conditions such as back pressure at the outlet, are set, and multiple different operating condition combinations are reasonably set. Then, mesh division is performed. Mesh refinement is performed in key areas of the turbine system, such as the blade surface, inlet and outlet, to improve calculation accuracy. At the same time, the quality of the entire mesh must meet the software requirements to avoid problems such as distortion. After that, an appropriate calculation model and solver are selected based on the properties and flow characteristics of the fluid. For example, if it is turbulent flow, an appropriate turbulence model should be selected, and a pressure-velocity coupling model should be set at the same time. The solver parameters should be reasonably set, such as the convergence accuracy should be high enough and the number of iterations should meet the calculation requirements.

[0031] Step S4: Calculate the primary energy conversion efficiency of the floating system and optimize the floating system. Perform relevant floating simulations based on the correlation model to calculate the primary energy conversion efficiency of the floating system.

[0032] Specifically, the designed air chamber opening model of the floating body system is imported into simulation software, wave loading conditions are set, and the primary energy conversion efficiency of the floating body is calculated. Based on the simulation results, if the efficiency standard is met, the design is finalized. If not, parameter iteration is performed to adjust the turbine system parameters to further optimize the floating body design and improve energy conversion efficiency.

[0033] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A rapid design method for the floating system of an oscillating water column wave energy device, characterized in that: The following steps are involved: Step S1, selecting a suitable turbine system type and determining the size, blade shape, and rotational speed of the turbine system according to the wave characteristics of the target sea area; Step S2, obtaining the performance parameters of the turbine system through numerical simulation and experimental testing, and simplifying the performance parameters of the turbine system; Step S3: Based on the simplified performance parameters of the turbine system, a correlation model between the turbine system and the floating body system is established, and wave boundary conditions are set; the flow field around the floating body system is meshed, and an appropriate turbulence model and solver are selected to perform steady-state or transient simulation; Step S4: Calculate the primary energy conversion efficiency of the floating system and optimize the floating system.

2. A rapid design method for a floating system of an oscillating water column wave energy device according to claim 1, characterized in that: Turbine system types include Welsh turbines and bidirectional turbines.

3. The rapid design method for the floating system of an oscillating water column wave energy device according to claim 1 is characterized in that: The numerical simulation and experimental test are to produce a scaled-down turbine system model according to the actual size and operating environment of the turbine system, and to carry out pressure drop experiments under different operating conditions of the turbine system.

4. The rapid design method for a floating system of an oscillating water column wave energy device according to claim 1 is characterized in that: The performance parameters of the turbine system obtained through numerical simulation and experimental testing include speed and flow rate.

5. A rapid design method for a floating system of an oscillating water column wave energy device according to claim 4, characterized in that: The performance parameters of the simplified turbine system include flow coefficient, pressure drop coefficient, and resistance model.

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