CN108398355B - A Method for Predicting Cigarette Burning Rate Based on Detection of Pressure Drop and Flow Field Distribution - Google Patents

Abstract

The invention discloses a method for predicting the burning rate of cigarettes based on detecting pressure drop and flow field distribution, which comprises using a pressure drop detection device to measure the mouth-by-puff pressure drop when a cigarette sample is sucked; using a flow detection device to measure the air flow at the combustion cone end; Using the burning rate detection device to measure the burning rate under the corresponding puffing sequence; taking the change of pressure drop from mouth to mouth and the air flow rate as the independent variables x ₁ and x ₂ respectively, and the burning rate y as the dependent variable, the regression of the cigarette burning rate prediction model is obtained Equation; After measuring the puff-to-puff pressure drop change and the air flow at the combustion cone end when other cigarettes are smoked, they are substituted into the prediction model to obtain the burning rate of the cigarette. It simplifies the experimental process of measuring the parameters of the cigarette burning characteristics, supplements the basic detection method of the burning rate and the unstable factors in the measurement, and simplifies the data processing in the traditional method. To provide basic data for further guiding research on cigarette materials, analysis of cigarette burning and smoking mechanism and design of cigarette materials.

Description

A Method for Predicting Cigarette Burning Rate Based on Detection of Pressure Drop and Flow Field Distribution

technical field

The invention relates to a method for predicting the burning rate of cigarettes, in particular to a method for predicting the burning rate of cigarettes based on detected pressure drop and flow field distribution.

Background technique

With the gradual strengthening of cigarette tar reduction and coke control, the test items that need further research are no longer covered by the test items and methods stipulated by the international regulations. Among them, the burning speed of cigarettes is due to its contribution to the release of cigarette tar. Be the one that stands out from being studied.

At present, the research on the burning rate of cigarettes mainly focuses on the smoldering rate (the average rate at which the burning line advances along the axial direction when the cigarette is not smoked), and there are few studies on the characterization of the instantaneous burning rate.

CN 203758946U discloses a device for measuring the burning rate of cigarettes. The device can track the change of the mass of the cigarette when it is burned, and at the same time capture the smoke, and calculate the burning mass loss rate of the cigarette according to the measured relevant data.

CN 106324181A collects the temperature distribution data of the combustion cone when the cigarette is burned, and uses the internal temperature of the combustion cone as the point movement of the characteristic temperature T0.5 to characterize the transient combustion rate of the cigarette.

CN 105527371A disclosed by this laboratory captures the signal of starting smoking by the cigarette smoking system through a synchronous trigger device and then transmits it to the controller. The burning rate is calculated.

Since the raw material composition of cigarettes, the characteristics of auxiliary materials, the loose structure inside the cigarette, the irregular temperature distribution and the fast gas flow rate can all affect the burning rate, the work of measuring the burning rate has very great guiding significance, so It is necessary to establish a method for detecting the burning rate of cigarettes, which can supplement the above methods.

During the burning and smoking process of cigarettes, mainstream smoke mainly enters from three areas, namely the burning end of the cigarette, the cigarette paper section of the main body of the cigarette, and the filter section with filter ventilation. With the development of smoking and health and low-tar and low-hazard cigarettes, tobacco companies are looking for technologies for low-tar cigarettes. Up to now, changing the air permeability of cigarette paper and changing the ventilation of cigarette filters have been used to reduce smoke tar. In essence, by adjusting auxiliary materials and other factors, what is finally changed is the air intake of each segment of the cigarette, thereby affecting the parameters of cigarette combustion characteristics. As one of the most important parameters of cigarette combustion characteristics, the combustion rate is closely related to the distribution of air flow in cigarettes. At the same time, the combustion rate of tobacco is limited by the mass transfer rate of oxygen reaching the tobacco surface, because the viscosity and velocity of gas in the combustion zone increase with temperature, so the combustion zone has relatively high resistance to airflow, which in turn affects the cigarette The overall pressure drop has an effect.

Therefore, in practical research, it is feasible and meaningful to explore the correlation among flow field distribution, pressure drop and combustion rate.

Contents of the invention

In order to solve the deficiencies of the prior art, the object of the present invention is to provide a method for quickly and accurately predicting the burning rate of cigarettes based on the detection of pressure drop and flow field distribution.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for predicting the burning rate of cigarettes based on detection of pressure drop and flow field distribution, comprising the following steps:

S1. Use the pressure drop detection device to measure the puff-by-puff pressure drop when the cigarette sample is smoked;

S2, using a flow detection device to measure the air flow at the combustion cone end when the cigarette sample is drawn;

S3. Use the burning rate detection device to measure the burning rate of the cigarette sample under the corresponding puff sequence, and record the burning rate value as y;

S4. Regression analysis: taking the pressure drop change from mouth to mouth of cigarettes and the air flow at the combustion cone end as independent variables x1 and x2 respectively, and burning rate y as dependent variable, the regression equation of the cigarette burning rate prediction model is obtained:

S5. Prediction of cigarette burning rate: After measuring the puff-to-puff pressure drop and the air flow at the combustion cone end when the cigarette is smoked, and then substituting it into the above prediction model, the burning rate of the cigarette can be obtained.

The method for detecting the pressure drop is as follows: a pressure sensor is placed in the suction port of the cigarette sample, and a processor is used to convert the measured pressure signal into a digital signal and output it in real time.

The above-mentioned pressure drop detection device includes a three-way valve, a pressure sensor, and a signal processor;

The input end of the three-way valve is connected to the suction port of the cigarette sample, and the two output ends are respectively connected to the suction machine and the processor through the pressure sensor;

The signal processor is connected to the controller, and the suction machine is connected to the controller through a synchronous trigger device.

The detection method of the air flow at the above-mentioned combustion cone end may further comprise the steps:

B1. Use the cigarette holder to clamp the cigarette sample, and use the connection between the filter section and the cigarette paper section as a partition to form two sections of sealed chambers;

B2. Light the cigarette, start the suction machine to suck the cigarette, and detect the air flow V1 of the cigarette paper section, the air flow V2 of the filter section and the total suction capacity V of the suction end;

B3. Based on the principle of flow balance, calculate the air flow V3=V-V1-V2 at the cigarette burning cone.

The above-mentioned combustion rate detection device includes a control module, a data processing module and an image acquisition module, and the image acquisition module is a camera;

The control module is connected with the suction machine, receives the suction signal of the suction machine and controls the camera to collect images of cigarette burning; the data processing module records and processes the collected images, and outputs data results.

Further, the shooting frequency of the above camera is 30-70Hz.

The duration of the single puff of the above cigarette single sample is 1-3s.

The above cigarette samples include blended and flue-cured cigarettes with a pressure drop ranging from 0 to 12 kPa.

The above cigarette samples include arbitrary circumference, length, filter ventilation and cigarette paper section ventilation.

The value calculation of the above model coefficients b ₁ , b ₂ , c includes the use of Origin software.

The benefits of the present invention are:

A method of predicting the burning rate of cigarettes based on the detected pressure drop and flow field distribution of the present invention, by performing regression analysis on the measured pressure drop and the air flow rate at the combustion cone end and the burning rate under the corresponding suction port sequence, to obtain the cigarette burning rate predictive model. For unknown cigarette samples, it is only necessary to measure the pressure drop of the cigarette and the air flow at the combustion cone, and use the prediction model to obtain the value of the burning rate.

A method of predicting the burning rate of cigarettes based on the detection of pressure drop and flow field distribution of the present invention simplifies the experimental process of determining the parameters of cigarette combustion characteristics, and the burning rate can be obtained by measuring the change of pressure drop and flow field distribution, that is, two groups of experiments can be Three sets of data are obtained; the basic detection method of the burning rate is supplemented, and the method can reduce the unstable factors in the determination of the burning rate; the data processing process in the traditional detection method of the burning rate is simplified. It provides basic data for further guiding research on cigarette materials, analysis of cigarette burning and smoking mechanism, and design of cigarette materials, and has strong applicability and wide applicability.

Description of drawings

Fig. 1 is a schematic structural diagram of a flow detection device of the present invention.

Fig. 2 is a schematic structural diagram of the pressure drop detection device of the present invention.

The meanings of the marks in the drawings are as follows: 1. Cigarette paper segment cavity, 2. Filter segment cavity, 3. Cavity body, 4. Side hole, 5. Baffle plate, 6. Seal ring, 7. Flow measurement component, 8. Cigarette holder, 9. Cigarette.

Detailed ways

The present invention will be specifically introduced below in conjunction with the accompanying drawings and specific embodiments.

The cigarette pressure drop in the present invention refers to the average value of the cigarette system pressure drop within the duration of each puff of a cigarette under different puffing modes.

The burning rate in the present invention refers to the instantaneous burning rate within the duration of each puff of a cigarette under different smoking modes.

Sampling: Use the conditions specified in GB/T 16447-2004 "Atmospheric Environment for Conditioning and Testing of Tobacco and Tobacco Products" to balance and select cigarette samples to collect the pressure drop, flow field distribution and Burn rate.

Cigarette samples include mixed cigarette samples or flue-cured cigarette samples with any circumference, any length, any filter tip ventilation and any cigarette paper section ventilation, and the pressure drop range is 0-12kPa.

A method for predicting the burning rate of cigarettes based on detection of pressure drop and flow field distribution, comprising the following steps:

S1. Use the pressure drop detection device to measure the puff-by-puff pressure drop of the cigarette sample when it is smoked.

The detection method of the pressure drop is as follows: a pressure sensor is placed in the suction port of the cigarette sample, and a processor is used to convert the measured pressure signal into a digital signal and output it in real time.

The pressure drop detection device of the present invention includes a three-way valve, a pressure sensor, and a signal processor; the input end of the three-way valve is connected to the suction port of the cigarette sample, and the two output ends are respectively connected to the suction machine and the processor through the pressure sensor; And the processor is connected to the controller, and the suction machine is connected to the controller through a synchronous trigger device.

S2. Using a flow detection device to measure the air flow at the combustion cone end when the cigarette sample is drawn.

The flow detection device of the present invention comprises a cigarette paper segment cavity 1, a filter segment cavity 2, a cavity 3, a side hole 4, a baffle 5, a sealing ring 6, a flow measurement component 7, a through hole (suction port) cigarette holder 8;

The inner end of the through hole is fixed to the cigarette 9, and the outer end is connected to the suction machine; the inner end of the cigarette holder 8 is connected to the cavity 3, and the cavity 3 is divided into the cigarette paper segment cavity 1 and the filter by the clamping ring and the cigarette 9. Mouth section cavity 2; the outer walls of the two sections of cavity 3 are telescopic walls, which are respectively connected to flow measuring components 7 through side holes 4; the end of the cigarette paper section cavity 1 is a baffle 5, and the inner ring of the baffle 5 is provided with The sealing ring 6 that the cigarette 9 contacts.

Measurement process: use the flow detection device to carry out ISO mode (35mL) suction on the tunnel suction machine, adjust the two chambers of the device according to the length of the cigarette filter rod and the length of the cigarette paper section under the corresponding suction port sequence, and select the appropriate seal according to the circumference of the cigarette Circle 6, so that the two sections of the cavity form a sealed air chamber; calibrate the zero flow measurement part 7, light the cigarette 9, start the cigarette 9 suction machine to suck; read the reading of the flow measurement part 7, and obtain the paper section of the cigarette 9 The air flow V ₁ and the air flow V ₂ entering the filter section, combined with the total suction capacity V of the suction end, use the formula V ₃ =VV ₁ -V ₂ to obtain the air flow V3 entering the burning cone end of the cigarette 9 .

The smoking process was carried out according to the conditions stipulated in GB/T 16450-2004 "Definition and Standard Conditions of Smoking Machines for Routine Analysis".

S3. Use the burning rate detection device to measure the burning rate of the cigarette sample under the corresponding puff sequence, and record the burning rate value as y.

The combustion rate detecting device of the present invention comprises a control module, a data processing module and a high-speed camera (acquisition frequency is 50 Hz); the control module is connected with the suction machine, receives the suction signal of the suction machine and controls the image of the camera when the cigarette 9 burns Collecting; the data processing module records and processes the collected images, and outputs data results.

Detection process: Pre-set the shooting parameters of the high-speed camera in the control module, such as shooting frequency, exposure, etc. Input the cigarette information to be tested in the suction machine software and the cigarette 9 burning speed measurement software (data processing module), and select a fixed length or a fixed number of suction ports for testing; after the information input is completed, click in turn on the cigarette 9 burning speed measurement software. "Start Test" and "Start Smoking" on the smoking machine software, immediately turn on the cigarette lighter to light the cigarette9.

When the cigarette 9 burns to the set length or the set number of puffs, the test ends, and the test result is queried in the software for measuring the burning speed of the cigarette 9 . The output result can display the instantaneous burning and smoldering speed of the cigarette 9 burning, and can also calculate the average smoking and smoldering speed of every puff of the cigarette 9 and the whole cigarette.

S4. Regression analysis: taking the pressure drop change from mouth to mouth of cigarettes and the air flow at the combustion cone end as independent variables x1 and x2 respectively, and burning rate y as dependent variable, the regression equation of the cigarette burning rate prediction model is obtained:

Use Origin software to calculate the values of model coefficients b ₁ , b ₂ , and c, and get the following table 1:

Table 1 Regression equation R ² and model coefficients of combustion cone air flow and combustion rate

It can be seen from Table 1 that R ² =0.927, indicating that the pressure drop of the cigarette system from mouth to mouth, the air flow rate at the combustion cone end and the combustion rate have obvious correlations, and the obtained correlation equation is:

S5. Prediction of cigarette burning rate: After measuring the puff-to-puff pressure drop and the air flow at the combustion cone end of the cigarette 9 when puffed, and substituting it into the above prediction model, the burning rate of the cigarette 9 can be obtained.

In order to further illustrate the predetermined effect achieved by the present invention, 8 brands of cigarette samples that did not participate in the modeling were used to detect the system pressure drop and the air flow at the combustion cone end of each sample when the third puff was drawn, and use the established regression equation to predict Its combustion rate when the third port sucks, on the other hand directly collects the combustion rate when the third port sucks. Comparing the difference of the burning rate of the third port suction under the two methods. The results are shown in Table 2:

Table 2 The comparison between the predicted value and the measured value of the burning rate of the third puff in the cigarette samples

The test results show that the difference between the predicted value and the measured value of the cigarette burning rate is small, and the relative error of the two in the eight groups of data is less than 10%, and the prediction result of the prediction model is relatively accurate.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the above-mentioned embodiments do not limit the present invention in any form, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims (10)

1. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate, which is characterized in that including following step It is rapid:

S1, using pressure drop detection means measurement cigarette sample aspirate when by mouth pressure drop；

S2, the air mass flow of burning tapered end when flow detector measurement cigarette sample suction is utilized；

S3, using the burn rate under the corresponding pump orifice sequence of burn rate detection means measure cigarette sample, by burn rate value It is denoted as y；

S4, regression analysis: with cigarette sample by mouth pressure drop and burning tapered end air mass flow be respectively independent variable x₁、x₂, burning speed Rate y is dependent variable, obtains the regression equation of cigarette burn rate prediction model:

S5, cigarette burn rate prediction: measurement cigarette smoking when by mouth change in pressure drop and burning tapered end air mass flow after, generation Enter above-mentioned prediction model to get the burn rate of the cigarette is arrived.

2. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the detection method of the pressure drop, are as follows: it is placed in pressure sensor in the pump orifice of cigarette sample, using processor The pressure signal of measurement is converted to digital signal to export in real time.

3. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the pressure drop detection means include triple valve, pressure sensor, signal processor；

The pump orifice of the input termination cigarette sample of the triple valve, two output ends connect suction machine respectively, pass through pressure sensing Device connects processor；

The processor connects controller, and suction machine connects controller by synchronous triggering device.

4. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the detection method of the air mass flow of the burning tapered end, comprising the following steps:

B1, cigarette sample is clamped using cigarette clamper, is partition with the joining place of filter segment and cigarette paper section, two sections of formation is close Seal chamber；

B2, lighting cigarette start suction machine smoking cigarette, detect the air mass flow V1 of cigarette paper section, the air mass flow of filter segment Total pumping volume V of V2 and aspiration end；

B3, it is based on flow equilibrium principle, calculates the air mass flow V3=V-V1-V2 of cigarette burning tapered end.

5. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the burn rate detection device includes control module, data processing module and image capture module, described image Acquisition module is camera；

Control module is connected with suction machine, receives the suction signal of suction machine and controls image progress of the camera to cigarette burning when Acquisition；Data processing module is recorded and is handled to acquired image, and output data result.

6. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 5, It is characterized in that, the frequency of the shooting of the camera is 30-70Hz.

7. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the duration of the cigarette single sample single port suction is 1-3s.

8. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the cigarette sample includes mixed type of the pressure drop range in 0-12kPa, Virginian-type cigarette.

9. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the cigarette sample includes arbitrary circumference, length, filter tip degree of ventilation and cigarette paper section degree of ventilation.

10. a kind of method based on detection pressure drop and Flow Field Distribution prediction cigarette burn rate according to claim 1, It is characterized in that, the model coefficient b₁、b₂, c exploitation, including use Origin software.