Intelligent control system and method for multifunctional cooking electric steamer

Abstract

The invention discloses an intelligent control system and method for a multifunctional cooking electric steamer, and the system comprises a steam generation unit which is provided with a fractal guide plate, the surface of the steam generation unit is provided with a gradient porosity metal foam layer, and the porosity is continuously and gradually changed in the steam flowing direction; the asymmetric pulse control unit is provided with an electromagnetic valve, is driven by a pulse signal with an adjustable duty ratio, and is used for enabling the steam flow guided out by the fractal flow guide plate to form high-low pressure alternating steam flow with a preset alternating period; the temperature field monitoring unit comprises a temperature sensor array distributed on the inner wall of the cooking cavity, and a space temperature field feedback network is formed to monitor the temperature in the cooking cavity and perform CFD simulation; and the dynamic injection adjusting unit adopts a rotary steam nozzle and is used for adjusting and controlling the injection angle of the nozzle in real time according to the CFD simulation result so as to inject high-low pressure alternate steam flow. According to the electric steamer, uniform distribution of steam flow in the electric steamer is realized, so that the problem that food is locally over-cooked or over-cooked is avoided, and the cooking efficiency and quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent control of electric steamers, and particularly to an intelligent control system and method for a multifunctional cooking electric steamer. Background Art

[0002] An electrode steam boiler uses electrode heating to generate steam that meets the requirements for users. The traditional electric steamer has a low steam generation efficiency and requires different powers for heating in segments, but usually there is a problem of uneven steam distribution, which cannot ensure uniform heating of the ingredients during cooking. As such, it cannot meet the complex requirements of different ingredients for different steam cooking environments, greatly limiting the cooking effect and the adaptability of ingredient types. Summary of the Invention

[0003] To solve at least one of the above-mentioned technical problems, the present invention provides an intelligent control system and method for a multifunctional cooking electric steamer.

[0004] In a first aspect, the present invention provides an intelligent control system for a multifunctional cooking electric steamer, the system comprising:

[0005] A steam generation unit provided with a fractal deflector, on the surface of which a gradient porosity metal foam layer is distributed, and the porosity is continuously changed along the steam flow direction;

[0006] An asymmetric pulse control unit provided with a solenoid valve, which is driven by a pulse signal with an adjustable duty cycle and is used to form a high-low pressure alternating steam flow with a preset alternating period from the steam flow led out by the fractal deflector;

[0007] A temperature field monitoring unit including a temperature sensor array distributed on the inner wall of the cooking cavity, forming a spatial temperature field feedback network for monitoring the temperature in the cooking cavity and performing CFD simulation;

[0008] A dynamic injection adjustment unit using a rotary steam nozzle for real-time adjusting the injection angle of the nozzle according to the CFD simulation results to inject the high-low pressure alternating steam flow.

[0009] Preferably, the fractal deflector adopts a Hilbert curve fractal configuration, and the branch spacing satisfies:

[0010] Δd = 0.8 n ×D

[0011] In the formula, Δd represents the branch spacing, n represents the fractal iteration times, n≥3, and D is the initial spacing.

[0012] Preferably, the porosity continuously changes by 50%-80% along the steam flow direction, and the porosity gradient distribution of the metal foam layer satisfies that the porosity at the inlet end is:

[0013]

[0014] In the formula, μ in represents the porosity at the inlet end, x is the axial position, and L is the total length of the channel.

[0015] Preferably, the preset alternating period is 2 - 5 seconds.

[0016] Preferably, the rotatable angle of the rotary steam distributor is 30° - 150°.

[0017] Preferably, the temperature sensor array is divided into a first layer, a second layer, and a third layer in sequence from the closest to the farthest from the bottom of the electric steamer, and the number of sensors in each layer decreases.

[0018] Preferably, the system further includes:

[0019] A scale cleaning unit, which is used to integrate quantum dot fluorescence probes, identify the water quality hardness through the characteristic emission spectrum, input the water quality hardness into a pre-trained LSTM model to predict the scale trend, and trigger the automatic citric acid cleaning program according to the prediction result.

[0020] In a second aspect, the present invention further provides a smart control method for a multifunctional cooking electric steamer, which is applied to the smart control system of the multifunctional cooking electric steamer as described in any item of the first aspect. The method includes:

[0021] Collecting temperature field data of the three-dimensional space inside the electric steamer through a temperature sensor array distributed on the inner wall of the cooking cavity;

[0022] Determining simulation parameters, including steam flow parameters and fractal deflector structure parameters, using the spray angle range of the nozzle as the boundary condition, and inputting the simulation parameters and boundary conditions into a CFD model for simulation;

[0023] Inverting the initial flow field based on the temperature field data, and using a transient turbulence model to solve the steam flow control equation to calculate the non-uniformity index of the flow field;

[0024] Judging whether the non-uniformity index exceeds a preset threshold. When the preset threshold is exceeded, calculating the nozzle angle correction amount to control the steam injection, triggering the solenoid valve to dynamically adjust the duration ratio of the high-pressure and low-pressure alternating steam flow according to the flow field uniformity until the non-uniformity index is within the preset threshold, forming a closed-loop control of the steam flow inside the electric steamer.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The intelligent control system of the multifunctional cooking electric steamer provided by the present invention drives the solenoid valve through a pulse signal with adjustable duty cycle to form a high-low pressure alternating steam flow, which can enhance the adaptability of food materials and ensure different steam supplies at different stages; by collecting temperature data and performing CFD simulation, the dynamic injection adjustment unit adopts a rotary steam nozzle, which can adjust the injection angle of the nozzle in real time according to the CFD simulation results to ensure that the high-low pressure alternating steam flow is accurately injected into each area of the cooking cavity, so that the food materials are evenly heated in a more suitable steam environment, significantly improving the cooking effect. Therefore, through the coordinated operation of the steam generation unit, the asymmetric pulse control unit, the temperature field monitoring unit and the dynamic injection adjustment unit, the present invention effectively solves the problems in the prior art such as unreasonable steam generation and distribution, inaccurate steam control, incomplete temperature monitoring and lack of flexibility in steam injection. It realizes the efficient generation and uniform distribution of steam, can accurately adjust the steam pressure and flow rate to match the cooking needs of different food materials, comprehensively and real-time monitor the temperature field in the cooking cavity and perform accurate control, and flexibly adjust the steam injection angle to ensure uniform heating of food materials, greatly improving the intelligence level and cooking effect of the cooking electric steamer.

[0027] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present disclosure. Brief Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background art, the following will describe the drawings required to be used in the embodiments of the present invention or the background art.

[0029] The drawings here are incorporated into the specification and form a part of this specification. These drawings show embodiments that conform to the present disclosure and are used together with the specification to illustrate the technical solutions of the present disclosure.

[0030] Figure 1 It is a schematic structural diagram of an intelligent control system of a multifunctional cooking electric steamer provided by an embodiment of the present invention;

[0031] Figure 2 It is a schematic structural diagram of an intelligent control system of a multifunctional cooking electric steamer provided by another embodiment of the present invention;

[0032] Figure 3 It is a schematic flow diagram of an intelligent control method of a multifunctional cooking electric steamer provided by an embodiment of the present invention. Detailed Description of the Embodiments

[0033] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0034] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0035] Currently, when an electric steamer is in use, there will be a problem of uneven steam flow distribution, which will cause local overheating or overcooling, and then result in overcooked or undercooked food materials, seriously affecting the cooking effect. For this reason, the present invention provides a multi-functional cooking electric steamer intelligent control system and method. Through the coordinated operation of a steam generation unit, an asymmetric pulse control unit, a temperature field monitoring unit, and a dynamic injection adjustment unit, the problems in the prior art such as unreasonable steam generation and distribution, inaccurate steam control, incomplete temperature monitoring, and lack of flexibility in steam injection are effectively solved.

[0036] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a multi-functional cooking electric steamer intelligent control system provided by an embodiment of the present invention. As Figure 1 shown, the multi-functional cooking electric steamer intelligent control system includes:

[0037] A steam generation unit 100, provided with a fractal flow guide plate, and a gradient porosity metal foam layer is distributed on the surface of the fractal flow guide plate, and the porosity gradually changes continuously along the steam flow direction;

[0038] An asymmetric pulse control unit 200, provided with an electromagnetic valve, and the electromagnetic valve is driven by a pulse signal with an adjustable duty cycle, and is used to form a high-low pressure alternating steam flow with a preset alternating period from the steam flow led out by the fractal flow guide plate;

[0039] A temperature field monitoring unit 300, including a temperature sensor array distributed on the inner wall of the cooking cavity, constituting a spatial temperature field feedback network, and is used to monitor the temperature in the cooking cavity and perform CFD simulation;

[0040] The dynamic injection adjustment unit 400, which adopts a rotary steam nozzle, is used to adjust the injection angle of the nozzle in real time according to the CFD simulation results so as to inject the high-low pressure alternating steam flow.

[0041] For the convenience of understanding, the following terms are first explained:

[0042] Fractal flow guide plate: Fractal is a geometric shape with self-similar characteristics. The fractal flow guide plate designs its shape using this characteristic, so that the flow path of steam on the flow guide plate presents a self-similar branched structure, which can effectively increase the contact area between steam and the flow guide plate, improve the steam flow guiding efficiency, and optimize the distribution of steam in the cooking cavity.

[0043] Gradient porosity metal foam layer: Metal foam is a metal material with a large number of pores inside. Gradient porosity means that the porosity gradually changes from the steam inlet to the outlet direction. Such a structure enables steam to flow rapidly in large pores when passing through the metal foam layer. As the pores become smaller, the steam is gradually dispersed and stabilized, reducing the turbulence and energy loss during the steam flow process, and at the same time playing a role in filtering impurities.

[0044] Pulse signal with adjustable duty cycle: A pulse signal is a periodic signal. In one cycle, the ratio of the time when the signal is at a high level to the entire cycle time is the duty cycle. Adjustable duty cycle means that this ratio can be changed through a control circuit or program. In this system, by adjusting the duty cycle, the time ratio of the solenoid valve opening and closing is controlled, thereby forming a high-low pressure alternating steam flow.

[0045] CFD simulation: CFD, that is, computational fluid dynamics, is to analyze a system containing physical phenomena such as fluid flow and heat conduction through computer numerical calculation and image display. In this system, using CFD simulation technology, based on the data collected by temperature sensors, the flow and temperature field distribution of steam in the cooking cavity are simulated, providing a basis for accurately adjusting steam parameters and injection angles.

[0046] In this embodiment, the cooperation relationship of each unit is as follows. In the steam generation unit 100, a fractal deflector plate and a gradient metal foam layer are adopted. Using the topology optimization algorithm, after the steam generation unit operates, the generated steam flow will flow along the pores of the gradient metal foam layer. In the asymmetric pulse control unit 200, there are a pulse signal generator and a solenoid valve. When the steam flows, the pulse signal generator will respond, adjust the pulse signal period through the duty cycle adjustment knob to generate a control signal, so as to control the size of the solenoid valve, and realize the alternating control of high-pressure steam flow and low-pressure steam flow. At the same time, the system will monitor the temperature field in the cooking cavity of the electric steamer through the temperature field monitoring unit 300, and combine CFD simulation technology to judge whether the non-uniformity index of the flow field is within the preset threshold. If it exceeds the threshold, it means the distribution is uneven. At this time, the dynamic injection adjustment unit 400 will use a rotary steam nozzle to adjust the injection angle of the nozzle in real time according to the CFD simulation results, and inject high and low pressure alternating steam flows in the cooking cavity until the non-uniformity index of the flow field can meet the standard, so as to realize the closed-loop control of steam flow and temperature field and ensure the cooking quality.

[0047] The fractal deflector plate can use high-precision 3D printing technology and select food-grade stainless steel materials. Before printing, use professional modeling software to accurately design the complex shape of the deflector plate according to the fractal principle to ensure that the steam flow path on its surface presents a highly self-similar branching structure. During the printing process, strictly control various parameters to ensure that the size accuracy of the deflector plate is within ±0.1 mm, so as to achieve efficient diversion of steam. The gradient porosity metal foam layer adopts chemical vapor deposition (CVD) technology, and the fractal deflector plate is placed in the deposition equipment. By accurately controlling parameters such as deposition time, reaction gas flow rate, and deposition temperature, for example, setting a longer time and a larger gas flow rate at the initial stage of deposition to make the porosity of the metal foam layer at the steam inlet reach 40%-50%, and gradually reducing the time and gas flow rate as the deposition process progresses, so that the porosity at the outlet is reduced to 20%-30%, thereby realizing the continuous change of porosity along the steam flow direction.

[0048] For the asymmetric pulse control unit, a microcontroller with stable performance such as the STM32 series can be selected for pulse signal generation. With the help of professional programming software, a program for generating a pulse signal with adjustable duty cycle is written. At the same time, a touch operation interface is set on the control panel of the electric steamer, or a supporting mobile phone APP is developed. Users can input different cooking modes (such as steaming fish, steaming buns, steaming vegetables, etc.) through the interface or APP, and the system automatically converts the cooking mode into the corresponding duty cycle value according to the preset algorithm, and then controls the opening and closing time ratio of the solenoid valve. The solenoid valve can be a pilot-operated solenoid valve with a high temperature resistance up to 150 °C and a response time within 5 ms. The solenoid valve is installed at a position on the steam pipe close to the outlet of the fractal deflector to ensure that it can quickly respond to the pulse signal and accurately switch the steam flow into a high and low pressure alternating steam flow with a preset alternating cycle.

[0049] The temperature sensor array preferably uses a thermistor temperature sensor with an accuracy of ±0.5 °C and is evenly distributed on the inner wall according to the shape and size of the cooking cavity. For a common 30L - 50L cooking cavity, the sensors are spaced 6 - 8 cm apart and fixed by a special sensor mounting bracket to ensure firmness and accurate temperature sensing inside the cavity. All sensors are connected to the data acquisition module through high-temperature resistant shielded cables. The data collected by the temperature sensors is transmitted to the computer in real time through the data acquisition module, and a precise three-dimensional model of the cooking cavity is established using software with a model accuracy reaching the millimeter level. Parameters such as the physical properties of the steam and the flow boundary conditions are set, and the software simulates the temperature field distribution inside the cavity according to the input data and presents it in the form of an intuitive temperature contour map. According to the simulation results, the system adjusts the relevant parameters of the steam generation unit and the dynamic injection adjustment unit through a control algorithm. The rotary steam nozzle can be a rotary steam nozzle driven by a stepper motor, and the nozzle material is selected as a high-performance ceramic with high temperature resistance and steam corrosion resistance. The stepper motor is connected to the microcontroller, and the microcontroller accurately calculates the angle and time for the nozzle to rotate based on the temperature field data obtained from the CFD simulation, and sends a control pulse signal to the stepper motor to achieve real-time control of the nozzle injection angle. The nozzle is installed at the top of the cooking cavity to ensure that the steam can evenly cover the ingredients inside the cavity. Additionally, a special control algorithm can be developed to enable the microcontroller to quickly and accurately adjust the nozzle angle according to the CFD simulation results. The algorithm takes into account factors such as the dynamic characteristics of steam flow, the rate of change of the temperature field, and the heat conduction characteristics of the ingredients to ensure that the high and low pressure alternating steam flow is accurately sprayed onto areas with lower temperature or denser ingredient distribution.

[0050] In the above-mentioned embodiment, the fractal-structured deflector's unique self-similar branching structure significantly increases the contact area between the steam and the deflector. Compared to traditional flat deflectors, this significantly improves steam diversion efficiency and evenly directs steam to all areas of the cooking chamber, reducing steam accumulation and localized overheating, ensuring uniform heating of food. The gradient porosity metal foam layer effectively stabilizes steam flow, reduces turbulence, and minimizes energy loss during steam flow. Furthermore, the porous structure filters out tiny impurities from the steam, ensuring steam purity and improving the quality of cooked food. Precise control of the solenoid valve via a pulse signal with adjustable duty cycle enables fine adjustment of steam pressure, allowing for multiple high- and low-pressure alternating modes to meet the specific steam pressure requirements of different ingredients. A temperature sensor array fully covers the cooking chamber, coupled with high-precision CFD simulation, enabling real-time and accurate monitoring of the temperature distribution within the chamber with an accuracy of ±1°C. Compared to traditional single-point or limited-point temperature monitoring, this system can promptly detect abnormal temperature areas within the chamber, preventing localized overheating or undercooking of food. By precisely adjusting the steam injection angle, the cooking time of ingredients can be shortened, while avoiding the problem of partially undercooked or over-cooked ingredients due to uneven steam distribution, significantly improving the cooking quality of ingredients.

[0051] In one embodiment, the fractal guide plate adopts a Hilbert curve fractal configuration, and the branch spacing satisfies:

[0052] Δd=0.8 n ×D

[0053] Where Δd represents the branch spacing, n represents the number of fractal iterations, n ≥ 3, and D is the initial spacing.

[0054] The Hilbert curve recursively divides the plane to form a continuous path without crossing. The step-by-step reduction in spacing can gradually break up the large-scale vortices in the steam flow, and the pressure difference distribution between adjacent layers tends to be flat. n The value 0.8 is close to the inverse of the golden ratio (0.618), taking into account fluid mechanics efficiency.

[0055] In one embodiment, the porosity varies continuously from 50% to 80% along the steam flow direction, and the porosity gradient distribution of the metal foam layer satisfies the following conditions: the porosity at the inlet end is:

[0056]

[0057] Where μ in represents the porosity at the inlet end, x is the axial position, and L is the total length of the channel.

[0058] In the formula, 0.5 is the basic porosity, which exists no matter where x is located. is the change in porosity, What is calculated is the proportion of the current position x in the total channel length L. After squaring it and then multiplying by 0.3, the resulting value is the porosity increment generated due to the position change. When x is 0, that is, at the channel entrance, is 0, and at this time μ in is 0.5, which conforms to the initial porosity value at the inlet end being 50%. As x increases, becomes larger, also becomes larger, and the porosity increment also becomes larger until x = L, that is, at the channel exit, μ in = 0.8, reaching the outlet end porosity of 80%. Through this formula, the porosity of the metal foam layer can be precisely controlled to continuously vary from 50% to 80% from the inlet to the outlet, optimizing the flow state of steam therein, stabilizing steam, reducing energy loss, and filtering impurities.

[0059] In one embodiment, the preset alternating period is 2 - 5 seconds. During implementation, through the programming settings of the microcontroller, the cycle duration of the duty - cycle adjustable pulse signal is precisely regulated. For example, when the user selects the steamed fish mode, the preset alternating period can be set to 3 seconds. Within these 3 seconds, the solenoid valve opens and closes according to the pulse signal with a specific duty cycle, forming an alternating high - and - low - pressure steam flow. Assuming the duty cycle is set to 60%, then within these 3 seconds, the solenoid valve is open for 1.8 seconds and closed for 1.2 seconds. The high - pressure steam flow lasts for 1.8 seconds, and the low - pressure steam flow lasts for 1.2 seconds. From the perspective of the impact on the steam flow, a shorter preset alternating period (such as 2 seconds) can make the high - and - low - pressure steam flow switch more frequently, causing the steam to stir more violently in the cooking cavity, accelerating heat transfer, and being applicable to small - volume and easily - cooked ingredients, quickly steaming the ingredients and ensuring their tender texture. While a longer preset alternating period (such as 5 seconds), the high - and - low - pressure steam flow switches relatively slowly, and the action of the steam is milder and more persistent, suitable for large - volume and difficult - to - cook ingredients, ensuring that the heat can penetrate deep into the ingredients and avoiding local overheating while steaming. In terms of cooking effects, taking the steaming of different ingredients as an example, when steaming shrimp, selecting a preset alternating period of 2 seconds, the shrimp can be evenly heated in a short time, and the shrimp meat is tender and elastic. This precise preset alternating period setting greatly improves the cooking adaptability of the electric steamer to different ingredients and significantly optimizes the cooking effect.

[0060] In one embodiment, the rotatable angle of the rotary steam distributor is 30° - 150°. Since the steam can be precisely sprayed onto the areas in the cooking cavity with lower temperature or more concentrated ingredient distribution, all parts of the ingredients are heated more evenly. Taking the steaming of a whole chicken as an example, when using a fixed - angle steam nozzle, the maturity difference between the chest and legs of the chicken may reach 15% - 20%, while after using a steam distributor that can rotate 30° - 150°, the maturity difference can be controlled within 8%. This makes the texture of the cooked ingredients more consistent and the tenderness more uniform, greatly improving the cooking quality.

[0061] In one embodiment, the temperature sensor array is divided into a first, second, and third layer, from closest to the bottom of the steamer to farthest, with the number of sensors decreasing in each layer. Specifically, the bottom layer (6-8 sensors) is positioned 20 mm from the bottom surface, the middle layer (4-6 sensors) is positioned 80 mm from the bottom surface, and the top layer (2-4 sensors) is positioned 140 mm from the bottom surface, thereby ensuring accurate temperature detection.

[0062] See also Figure 2 In one embodiment, the system further comprises:

[0063] The scale removal unit 500 is used to integrate quantum dot fluorescent probes, identify water hardness through characteristic emission spectra, and input water hardness into a pre-trained LSTM model to predict scale trends. The predicted results trigger the citric acid automatic cleaning program.

[0064] In this embodiment, the quantum dot fluorescent probe can be a quantum dot fluorescent probe that has high sensitivity and specific response to key ions in water that affect water hardness, such as calcium and magnesium ions. These quantum dot fluorescent probes will emit characteristic emission spectra related to ion concentrations under the excitation of light of a specific wavelength. For example, a quantum dot fluorescent probe based on a CdSe / ZnS core-shell structure is selected, and its detection limit for calcium ions can reach the nanomolar level. The quantum dot fluorescent probe is fixed on the surface of a special sensor chip, which is encapsulated in a waterproof, corrosion-resistant casing and installed in the water inlet pipe of the electric steamer or the bottom of the water tank to ensure full contact with water. Through microfluidic technology, water flows through the probe area to ensure that the ions in the water fully react with the probe.

[0065] Furthermore, a small fluorescence spectrometer is built into the scale removal unit 500 to excite the quantum dot fluorescent probe and detect its emission spectrum. The spectrometer emits light of a specific wavelength, such as 365nm ultraviolet light, onto the quantum dot fluorescent probe and then collects the fluorescence spectrum emitted by the probe. The spectrometer transmits the collected spectral data via a data cable to the electric steamer's main control chip. The main control chip performs preliminary processing on the data and extracts characteristic parameters of the spectrum, such as peak wavelength and fluorescence intensity, which are closely related to water hardness.

[0066] After detecting the water quality hardness, it is necessary to further predict the scale trend, which can be achieved by combining with the LSTM model. When training the model, it is necessary to collect a large amount of water sample data with different water quality hardness, including the corresponding spectral characteristic parameters and the actually measured water quality hardness values. Preprocess these data, such as normalization, to make the data within a unified scale range for convenient model training. Divide the preprocessed data into a training set and a test set, use the training set to train the model, and adjust the model parameters so that the model can accurately predict the water quality hardness according to the spectral characteristic parameters. After multiple rounds of training and optimization, the prediction accuracy of the model on the test set reaches more than 90%. Deploy the trained LSTM model to the main control chip of the electric steamer. The main control chip predicts the water quality hardness based on the spectral data collected by the quantum dot fluorescence probe, and further predicts the scale generation trend. For example, according to the historical data and the current water quality hardness, predict the possible scale accumulation amount in the next week. The trigger of the citric acid automatic cleaning program is determined by the scale generation trend. Set the scale accumulation threshold in the control system of the electric steamer. When the scale accumulation amount predicted by the LSTM model exceeds this threshold, the citric acid automatic cleaning program is automatically triggered. For example, when it is predicted that the scale accumulation amount in the next week will reach the level that affects the performance of the electric steamer, the system starts the cleaning program. When the cleaning program is triggered, the automatic injection device injects the citric acid solution into the water in the steam generation unit according to the preset ratio. Then, the electric steamer starts the steam generation program to make the steam containing citric acid circulate in the cooking cavity and dissolve the scale through chemical reactions. After the cleaning is completed, the automatic drainage device drains the cleaned water out of the electric steamer.

[0067] In this way, through the quantum dot fluorescence probe and spectral detection technology, the water quality hardness can be quickly and accurately identified. Using the pre-trained LSTM model to predict the scale trend can predict the scale accumulation situation in advance, and trigger the citric acid automatic cleaning program in time according to the prediction results, and clean before a large amount of scale accumulates, effectively reducing the impact of scale on the performance of the electric steamer.

[0068] See Figure 3 , in one embodiment, the present invention also provides a smart control method for a multifunctional cooking electric steamer, which is applied to the smart control system of the multifunctional cooking electric steamer as described in any one of the above embodiments. The method includes:

[0069] S10. Collect the temperature field data of the three-dimensional space inside the electric steamer through the temperature sensor array distributed on the inner wall of the cooking cavity;

[0070] S20. Determine the simulation parameters, including the steam flow parameters and the fractal deflector structure parameters. Taking the spray angle range of the nozzle as the boundary condition, input the simulation parameters and the boundary condition into the CFD model for simulation;

[0071] S30. Invert the initial flow field based on the temperature field data, and use the transient turbulence model to solve the steam flow control equation to calculate the non-uniformity index of the flow field;

[0072] S40. Determine whether the non-uniformity index exceeds the preset threshold. When it exceeds the preset threshold, calculate the nozzle angle correction amount to control the steam injection, and trigger the solenoid valve to dynamically adjust the duration ratio of the high-low pressure alternating steam flow according to the flow field uniformity until the non-uniformity index is within the preset threshold, forming a closed-loop control of the steam flow inside the electric steamer.

[0073] For the convenience of understanding, the control process will be elaborated in detail below:

[0074] 1) Collect three-dimensional space temperature field data {T(x, y, z, t)} through a temperature sensor array distributed on the inner wall of the cooking cavity, with 12 - 14 sensors and a sampling period of 0.5 - 2 seconds;

[0075] 2) Build a real-time computational fluid dynamics (CFD) simulation model, and the input parameters include:

[0076] Steam flow parameters: velocity in the pulsed high-pressure stage is 3 - 5 m / s, velocity in the low-pressure stage is 1 - 2 m / s, and the period T = 2 - 5 seconds;

[0077] Structural parameters: Hilbert curve fractal series n ≥ 3 of the fractal deflector, and the porosity distribution function of the metal foam

[0078]

[0079] Dynamic boundary condition: nozzle angle θ(t) ∈ [30°, 150°]

[0080] 3) Invert the initial flow field based on the temperature field data {T(x, y, z, t)}, and use the transient SST k-ω turbulence model to solve the steam flow control equation:

[0081]

[0082] In the formula, ρ is the steam density, with the unit of kg / m 3 , ui is the velocity vector component, i = x, y, z, which is used to describe the three-dimensional velocity distribution of the flow field and determines the convection intensity; p represents the static pressure, μ represents the dynamic viscosity, μt is the turbulent viscosity, Sporous represents the porous medium source term, K represents the permeability, and β represents the inertial resistance coefficient.

[0083] 4) Determine the non-uniformity index of the flow field:

[0084]

[0085] In the formula, η(t) is the dimensionless non-uniformity, V represents the effective volume of the cooking cavity, and ū(t) is the instantaneous spatial average velocity; u(x,t) is the component of the velocity vector on the x-axis. When η(t) > 0.08, it indicates the existence of a local low-speed area (which may easily lead to undercooked food) or a high-speed concentrated flow (which may lead to overcooking), and the nozzle adjustment needs to be triggered.

[0086] Calculate the nozzle angle correction amount through the adjoint optimization algorithm:

[0087]

[0088] In the formula, J is the multi-objective loss function, δ is the regularization coefficient, and Δθ k represents the angle correction amount of the kth nozzle;

[0089] 5) Determine the updated nozzle angle θ k (t + Δt) according to the angle correction amount, and generate vector steam injection:

[0090] θ k (t + Δt) = θ k (t) + Δθ k

[0091] 6) Trigger the asymmetric pulse control module to dynamically adjust the high-low pressure duration ratio according to the flow field uniformity:

[0092]

[0093] In the formula, t high 、t low are the high-pressure and low-pressure steam flow durations respectively, sigmoid is the sigmoid function. By adjusting the high-low pressure duration ratio in this way, a closed-loop control is formed until η(t) ≤ 0.08.

[0094] In summary, the intelligent control method provided in this embodiment collects temperature data and performs CFD simulation. The dynamic injection adjustment unit uses a rotary steam nozzle, which can adjust the injection angle of the nozzle in real time according to the CFD simulation results, ensure that the high-low pressure alternating steam flow is accurately injected into each area of the cooking cavity, make the food materials evenly heated in a more suitable steam environment, and significantly improve the cooking effect.

[0095] In one embodiment, after cooking is completed, an integrated quantum dot fluorescence probe may be further included to identify the water quality hardness through the characteristic emission spectrum, input the water quality hardness into a pre-trained LSTM model to predict the scale trend, and trigger the automatic citric acid cleaning program according to the prediction result. Specifically, the water quality hardness detection and scale trend prediction processes may refer to the foregoing embodiments. In this way, through the quantum dot fluorescence probe and spectral detection technology, the water quality hardness can be quickly and accurately identified. Using the pre-trained LSTM model to predict the scale trend can predict the accumulation of scale in advance, and trigger the automatic citric acid cleaning program in time according to the prediction result, and clean before a large amount of scale accumulates, effectively reducing the impact of scale on the performance of the electric steamer.

[0096] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0097] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein. Those skilled in the art can also clearly understand that each embodiment of the present invention has different emphases. For the convenience and brevity of description, the same or similar parts may not be elaborated in different embodiments. Therefore, the parts not described or not detailedly described in a certain embodiment can refer to the records of other embodiments.

Claims

1. A smart control system for a multifunctional cooking electric steam cooker, characterized in that, The system includes: A steam generation unit, provided with a fractal flow guide plate, on the surface of which a gradient porosity metal foam layer is distributed, and the porosity shows a continuous gradual change along the steam flow direction; An asymmetric pulse control unit, provided with a solenoid valve, which is driven by a pulse signal with an adjustable duty cycle and is used to form a high-low pressure alternating steam flow with a preset alternating period from the steam flow led out by the fractal flow guide plate; A temperature field monitoring unit, including a temperature sensor array distributed on the inner wall of the cooking cavity, constituting a spatial temperature field feedback network, and is used to monitor the temperature in the cooking cavity and perform CFD simulation; A dynamic injection adjustment unit, adopting a rotary steam nozzle, and is used to adjust the injection angle of the nozzle in real time according to the CFD simulation result to inject the high-low pressure alternating steam flow.

2. The intelligent control system of the multifunctional cooking electric steam cooker according to claim 1, wherein The fractal flow guide plate adopts a Hilbert curve fractal configuration, and the branch spacing satisfies: Δd = 0.8 n × D In the formula, Δd represents the branch spacing, n represents the fractal iteration times, n≥3, and D is the initial spacing.

3. The intelligent control system of the multifunctional cooking electric steamer according to claim 1, characterized in that, The porosity shows a continuous gradual change of 50%-80% along the steam flow direction, and the gradient distribution of the porosity of the metal foam layer satisfies that the porosity at the inlet end is: where μ in represents the porosity at the inlet end, x is the axial position, and L is the total length of the channel.

4. The intelligent control system of the multifunctional cooking electric steam cooker according to claim 1, characterized in that The preset alternating period is 2-5 seconds.

5. The intelligent control system of the multifunctional cooking electric steam cooker according to claim 1, characterized in that, The rotatable angle of the rotary steam distributor is 30°-150°.

6. The intelligent control system of the multifunctional cooking electric steamer according to claim 1, wherein, The temperature sensor array is successively divided into a first layer, a second layer and a third layer from the closest to the farthest from the bottom of the electric steamer, and the number of sensors in each layer decreases.

7. The intelligent control system of the multifunctional cooking electric steam pot according to claim 1, characterized in that The system further includes: A water scale cleaning unit, used to integrate quantum dot fluorescence probes, identify the water quality hardness through the characteristic emission spectrum, input the water quality hardness into a pre-trained LSTM model to predict the water scale trend, and trigger the automatic citric acid cleaning program according to the prediction result.

8. A smart control method for a multi-functional cooking electric steamer, which is applied to the smart control system of the multi-functional cooking electric steamer according to any one of claims 1-8, characterized in that, The method includes: Collecting the temperature field data of the three-dimensional space inside the electric steamer through the temperature sensor array distributed on the inner wall of the cooking cavity; Determining the simulation parameters, including steam flow parameters and fractal flow guide plate structure parameters, using the injection angle range of the nozzle as the boundary condition, and inputting the simulation parameters and boundary conditions into the CFD model for simulation; Inverting the initial flow field based on the temperature field data, using a transient turbulence model to solve the steam flow control equation to calculate the non-uniformity index of the flow field; Judging whether the non-uniformity index exceeds the preset threshold. When it exceeds the preset threshold, calculating the nozzle angle correction amount to control the steam injection, triggering the solenoid valve to dynamically adjust the duration ratio of the high-low pressure alternating steam flow according to the flow field uniformity until the non-uniformity index is within the preset threshold, forming a closed-loop control of the internal steam flow of the electric steamer.

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