A method for predicting local and overall thermal resistance of a clothing system based on a three-dimensional model
By constructing a three-dimensional model of the bedding system and the sleeping human body, calculating the surface area ratio coefficient of each part and establishing the heat transfer equation, and using the parallel method to calculate the thermal resistance, the problem of high cost and low efficiency in measuring the thermal resistance of the bedding system is solved, achieving efficient and accurate thermal resistance prediction and improving the thermal comfort of home textile products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-01-17
- Publication Date
- 2026-03-20
AI Technical Summary
Existing thermal resistance measurement systems for clothing are costly and inefficient, making them difficult to widely apply to academics and businesses.
A three-dimensional model-based approach was adopted to construct a three-dimensional geometric model of the bedding system and the sleeping human body. By calculating the surface area ratio coefficient of each part, a heat transfer equation was established, and the local and overall thermal resistance was calculated using a parallel method.
It reduces the cost of thermal resistance measurement, improves measurement efficiency, and the predicted results are similar to those of the heated mannequin. It can assess the thermal resistance values of different quilts, mattresses, human postures, and bedding coverage areas, thereby improving the thermal comfort of home textile products.
Smart Images
Figure CN116011235B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a three-dimensional model-based sleepwear system local and overall thermal resistance prediction method, belonging to the technical field of textile engineering. BACKGROUND
[0002] Sleepwear system is one of the key factors affecting human sleep thermal comfort, which is composed of bedding and clothing, usually including quilt, pillow, mattress, pajamas, etc.
[0003] The sleepwear system blocks the human body from the external environment, thereby reducing heat exchange between the human body and the external environment, and plays a role in keeping warm. The thermal performance of the sleepwear system can be characterized by thermal resistance, which is related to the thermal performance of each component of the sleepwear system, the posture of the sleeping human body, the coverage area of the sleepwear, and other factors.
[0004] Currently, the thermal resistance of the sleepwear system is mainly measured by a thermal manikin in a climate chamber with constant temperature and humidity control, which can obtain relatively accurate overall thermal resistance and local thermal resistance of different parts of the human body. However, the measurement instrument is expensive, the measurement conditions are harsh, and the operation is complex, making the current sleepwear system thermal resistance measurement cost very high, and the measurement efficiency is low, which is not convenient for application by scholars and enterprises. SUMMARY
[0005] In order to reduce the cost of sleepwear system thermal resistance measurement and improve the measurement efficiency, the present application provides a three-dimensional model-based sleepwear system local and overall thermal resistance prediction method, the technical solution is as follows:
[0006] Step 1: Construct a three-dimensional geometric model of the sleepwear system and the sleeping human body, and obtain the proportion coefficient of the body surface area of different parts of the human body contacting the quilt, contacting the air layer under the quilt, contacting the mattress and exposing to the external environment to the total body surface area based on the model;
[0007] Step 2: Based on the body surface area of different parts of the human body contacting the quilt, contacting the air layer under the quilt, contacting the mattress and exposing to the external environment obtained in step 1, establish the heat transfer equation of the human body local;
[0008] Step 3: Calculate the local thermal resistance of the sleepwear system by parallel method;
[0009] Step 4: Calculate the overall thermal resistance according to the local thermal resistance of the sleepwear system.
[0010] Optionally, the heat transfer equation of the human body local in step 2 includes: the heat transfer equation of the part contacting the quilt, the heat transfer equation of the part contacting the air layer under the quilt, the heat transfer equation of the part contacting the mattress and the heat transfer equation of the part exposed to the external environment;
[0011] The heat transfer calculation formula of the part contacting the quilt is:
[0012]
[0013]
[0014] wherein, is the total heat dissipation of the contact quilt part; is the body surface area of the contact quilt part; and are the human skin temperature and the external environment temperature, respectively; is the total thermal resistance of the contact quilt part; is the thermal resistance of the quilt; is the dry heat transfer coefficient of the quilt surface;
[0015] The heat transfer calculation formula of the contact quilt lower air layer part is:
[0016]
[0017] wherein, is the total heat dissipation of the contact quilt lower air layer part; is the body surface area of the contact air layer part; is the total thermal resistance of the contact quilt lower air layer part;
[0018] The heat of the contact quilt lower air layer part is first transferred to the quilt lower air layer, and then transferred to the external environment through the quilt and the mattress two parts, and the calculation formula is:
[0019]
[0020]
[0021]
[0022]
[0023] wherein, is the temperature of the quilt lower air layer; , and are the thermal resistances of the heat transferred to the quilt lower air layer, transferred to the external environment through the quilt, and transferred through the mattress, respectively; and are the heat transfer areas of the heat transferred through the quilt and the mattress, respectively; and are the dry heat transfer coefficients of the skin surface contacting the quilt lower air layer and the quilt surface, respectively; is the thermal resistance of the mattress;
[0024] The following formula is obtained from the above calculation formula:
[0025]
[0026] Therefore,
[0027]
[0028] wherein, and are the proportionality coefficients of the heat transfer area of the quilt and the mattress to the surface area of the contact air layer, respectively;
[0029] The heat transfer of the contact mattress part is calculated by the formula:
[0030]
[0031]
[0032] wherein, is the total heat dissipation of the contact mattress part; is the surface area of the contact mattress part; is the total thermal resistance of the contact mattress part;
[0033] The heat transfer of the exposed external environment part is calculated by the formula:
[0034]
[0035]
[0036] wherein, is the total heat dissipation of the exposed external environment part; is the surface area of the exposed external environment part; is the total thermal resistance of the exposed external environment part.
[0037] Optionally, the calculation formula of the local thermal resistance of the bedding system in step 3 is as follows:
[0038]
[0039] wherein, is the local thermal resistance; is the local surface area; , , , are the proportionality coefficients of the local surface area of the contact quilt, the contact air layer, the contact mattress and the exposed external environment to the total surface area of the part, respectively.
[0040] Optionally, the calculation formula of the overall thermal resistance of the bedding system in step (4) is as follows:
[0041]
[0042] wherein, R is the overall thermal resistance of the bedding system; A is the local body surface area; R is the local thermal resistance.
[0043] Optionally, step 1 adopts three-dimensional virtual technology to construct a three-dimensional geometric model of the bedding system and the sleeping human body.
[0044] Optionally, the human body parts include head, chest, abdomen, back, hips, upper arm, forearm, hand, thigh, lower leg, and foot.
[0045] Optionally, step 1 further includes denoising, repairing, and hole filling of the model of the bedding system and the sleeping human body in Geomagic image processing technology software.
[0046] Optionally, step 1 exports OBJ files of the bedding system model and the sleeping human body model, respectively, aligns the processed bedding system and sleeping human body geometric models, uses 3D comparison function to export deviation values of the two models, and obtains proportional coefficients of the body surface area of different parts contacting the quilt, contacting the air layer under the quilt, contacting the mattress, and exposed to the external environment, and the total body surface area of the parts.
[0047] Optionally, the bedding system model includes an inner quilt and a mattress.
[0048] Optionally, the sleeping human body geometric model includes a human body and a mattress.
[0049] The present application has the following advantages:
[0050] The present application uses a three-dimensional model to predict the overall and local thermal resistance of the bedding system, avoids the use of a thermal manikin and expensive measuring instruments, effectively reduces the measurement cost, and the thermal resistance measurement method of the present application is easy to operate, can improve the prediction efficiency, the prediction result of the present application is similar to the measurement result of the thermal manikin, can be used to predict the thermal resistance value under different quilt, mattress, human body posture, and bedding coverage area, is helpful for judging the warmth performance of the bedding system, and improves the thermal comfort of the use of home textile products. BRIEF DESCRIPTION OF DRAWINGS
[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0052] Figure 1 is a flowchart of the embodiment of the present application.
[0053] Figure 2 Fig. 1 is a schematic diagram of a model constructed using three-dimensional virtual technology and a geometric model of a sleeping human body for analysis.
[0054] Figure 3 Fig. 2 is a schematic diagram of heat transfer of a human body part and an air layer part in contact.
[0055] Figure 4 Fig. 3 is a cross-sectional view of a human body part in a lying position and a lying position.
[0056] Figure 5 Fig. 4 is a local clothing system thermal resistance result of an embodiment of the present application.
[0057] Figure 6 Fig. 5 is an overall clothing system thermal resistance result of an embodiment of the present application. DETAILED DESCRIPTION
[0058] To make the purpose, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application in combination with the drawings.
[0059] Embodiment One:
[0060] The embodiment provides a clothing system thermal resistance prediction method, referring to Fig. 1, and the specific process includes: Figure 1
[0061] Step 1: Construct a three-dimensional geometric model of a clothing system and a sleeping human body, and obtain the proportionality coefficient of the body surface area of different parts of the human body in contact with a quilt, an air layer under the quilt, a mattress and exposed to the external environment and the total body surface area of the part based on the model;
[0062] Step 2: Based on the body surface area of different parts of the human body in contact with a quilt, an air layer under the quilt, a mattress and exposed to the external environment obtained in step 1, establish a heat transfer equation of a human body part;
[0063] Step 3: Calculate the local thermal resistance of the clothing system using a parallel method;
[0064] Step 4: Calculate the overall thermal resistance according to the local thermal resistance of the clothing system.
[0065] Embodiment Two:
[0066] The embodiment provides a clothing system thermal resistance prediction method, as shown in Fig. 2, including the following steps: Figure 1
[0067] Step (1): Construct a three-dimensional geometric model of a clothing system and a sleeping human body;
[0068] Step (2): Establish a heat transfer equation of a human body part;
[0069] Step (3): Calculate the local thermal resistance of the clothing system using the parallel method;
[0070] Step (4): Calculate the overall thermal resistance based on the local thermal resistance of the clothing system.
[0071] This embodiment uses the thermal resistance prediction of a clothing system covered by four different weights of single blankets for the whole body (excluding the head) under supine and side-lying sleeping positions as an example to further illustrate the thermal resistance prediction method of the clothing system of the present invention.
[0072] Step (1): Construct a three-dimensional geometric model of the bedding system and the sleeping human body. The model in this embodiment is constructed using three-dimensional virtual technology, such as... Figure 2 As shown in section a on the left. Export the models of the styling system and the sleeping human body as OBJ files, as follows: Figure 2 The bedding system model shown in section b on the right includes an inner quilt and a mattress, while the sleeping human body model includes a human body and a mattress. The bedding system and sleeping human body models were optimized using Geomagic image processing software, including denoising, repair, and hole filling. The human body geometric model was segmented into 11 parts: head, chest, abdomen, back, buttocks, upper arm, forearm, hand, thigh, calf, and foot. The processed bedding system and sleeping human body geometric model were fitted and aligned. The deviation value between the two models was derived using the 3D comparison function, obtaining the ratio of the body surface area in contact with the quilt, the air layer under the quilt, the mattress, and the external environment to the total surface area of that part.
[0073] Step (2): Establish the heat transfer equation for a specific part of the human body. For example... Figure 3 As shown in section a on the left, the local heat transfer of the human body is divided into four parts: (1) heat transfer of the part in contact with the quilt; (2) heat transfer of the part in contact with the air layer under the quilt; (3) heat transfer of the part in contact with the mattress; and (4) heat transfer of the part exposed to the external environment.
[0074] (1) The heat transfer in contact with the quilt is calculated using the following formula:
[0075]
[0076]
[0077] in, The total heat dissipation of the part in contact with the blanket, in W; m is the surface area of the part of the body in contact with the blanket. 2 ; and These represent human skin temperature and ambient temperature, respectively, in °C. For the total thermal resistance of the contact quilt part, m 2 K / W; m 2 K / W; m 2 K.
[0078] (2) The heat transfer of the part of the air layer under the quilt, the calculation formula is:
[0079]
[0080] wherein, W; is the total heat dissipation of the part of the air layer under the quilt; m 2 ; m 2 K / W.
[0081] As shown in part b of the right side, the heat of this part is first transferred to the air layer under the quilt, and then can be transferred to the external environment through the quilt and the mattress, the calculation formula is: Figure 3
[0082]
[0083]
[0084]
[0085]
[0086] wherein, ℃; is the temperature of the air layer under the quilt; , and are the heat resistances of the heat transfer to the air layer under the quilt, through the quilt to the external environment and through the mattress, respectively, m 2 K / W; and are the heat transfer areas of the heat transfer through the quilt and the mattress, respectively, m 2 ; and are the dry heat transfer coefficients of the skin surface and the quilt surface contacting the air layer under the quilt, respectively, W / m 2 K; m 2 K / W.
[0087] The following formula can be obtained from the above calculation formula:
[0088]
[0089] Therefore,
[0090]
[0091] wherein, and are the proportionality coefficients of the heat transfer area of the quilt and the mattress to the surface area of the contact air layer, respectively.
[0092] (3) Heat transfer of the contact mattress part, the calculation formula is:
[0093]
[0094]
[0095] wherein, is the total heat dissipation of the contact mattress part, W; is the surface area of the contact mattress part, m 2 ; is the total thermal resistance of the contact mattress part, m 2 ·K / W.
[0096] (4) Heat transfer of the exposed external environment part, the calculation formula is:
[0097]
[0098]
[0099] wherein, is the total heat dissipation of the exposed external environment part, W; is the surface area of the exposed external environment part, m 2 ; is the total thermal resistance of the exposed external environment part, m 2 ·K / W.
[0100] Step (3): Calculate the local thermal resistance of the quilt system by using the parallel method, the calculation formula is as follows:
[0101]
[0102] wherein, is the local thermal resistance, m 2 ·K / W; is the local surface area, m 2 ; , , , are the proportionality coefficients of the local surface area of the contact quilt, the contact air layer under the quilt, the contact mattress and the exposed external environment to the total surface area of the part, respectively.
[0103] Dry heat exchange coefficient , , and This includes both radiative heat transfer coefficient and natural convection heat transfer coefficient. The radiative heat transfer coefficient of a human body when lying flat is 3.27 W / m². 2 K, the natural convection heat transfer coefficient is 5.1 / m 2 K, therefore the dry heat transfer coefficient , , and Both are 8.37 W / m 2 ·K.
[0104] like Figure 4 As shown in section a above, when lying flat, the skin surfaces of the chest, abdomen, and back are approximately parallel to the surfaces of the blanket and mattress, respectively. Therefore, the skin surfaces of the chest and abdomen... and The numbers are 1 and 0 respectively, while the back... and The values are 0 and 1 respectively. When lying flat, the skin surface of the limbs forms a certain angle θ≈60° with the surface of the blanket and mattress, therefore the limbs... and They are respectively and .like Figure 4 As shown in section b below, when lying on one's side, the skin surface of the chest, abdomen, and back forms a certain angle θ≈80° with the surface of the blanket and mattress. Therefore, the skin surface of the chest, abdomen, and back... and They are respectively and When lying on your side, the skin surface of the upper half of your limbs is approximately parallel to the surface of the blanket, while the skin surface of the lower half of your limbs forms a certain angle θ≈45° with the surface of the blanket and mattress. Therefore, the limbs... and They are respectively and .
[0105] Tables 1 and 2 provide the calculated parameters for the thermal resistance of the clothing system in the supine and lateral sleeping positions, respectively, for the head, chest, abdomen, back, buttocks, upper arm, forearm, hand, thigh, calf, and foot areas in the embodiments. , , , , , Table 3 provides basic information and thermal resistance of the four types of quilts and mattresses in the embodiments. The results of calculating the local thermal resistance of the bedding system at these 11 locations are as follows: Figure 5 The ak part is shown in the image. Figure 5The a-k parts in the table 1 also give the local thermal resistance of the clothing system in the thermal manikin test, and it can be seen that the prediction result is in good agreement with the thermal manikin test result, and the measurement accuracy of the clothing system thermal resistance is met.
[0106] Step (4): calculating the overall thermal resistance according to the local thermal resistance of the clothing system, and the calculation formula is as follows:
[0107]
[0108] wherein, is the overall thermal resistance of the clothing system, m 2 · K / W. is the local body surface area, m 2 as shown in the table 2. is the local thermal resistance, m 2 · K / W.
[0109] Table 1. Calculation parameters of the local thermal resistance of the clothing system in the lying posture
[0110]
[0111] Table 2. Calculation parameters of the local thermal resistance of the clothing system in the lying posture
[0112]
[0113] Table 3. Basic information of the quilt and the mattress
[0114]
[0115] The prediction result of the overall thermal resistance of the clothing system in the four weights of the quilt and the two sleep postures in the embodiment is shown in the table 4. Figure 6 Figure 6 The overall thermal resistance of the clothing system in the thermal manikin test is also given, and it can be seen that the prediction result is in good agreement with the thermal manikin test result, and the measurement accuracy of the clothing system thermal resistance is met.
[0116] The part steps in the embodiment of the application can be realized by using software, and the corresponding software program can be stored in a readable storage medium, such as an optical disc or a hard disc.
[0117] The above description is only the preferred embodiment of the application, and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.
Claims
1. A method for predicting the thermal resistance of a clothing system, characterized in that, The method for predicting the thermal resistance of the clothing system includes: Step 1: Construct a three-dimensional geometric model of the bedding system and the sleeping human body, and based on the model, obtain the ratio of the surface area of different parts of the human body in contact with the blanket, the air layer under the blanket, the mattress, and the external environment to the total surface area of that part. Step 2: Based on the surface area of different parts of the human body in contact with the quilt, the air layer under the quilt, the mattress, and the external environment obtained in Step 1, establish the local heat transfer equation of the human body. Step 3: Calculate the local thermal resistance of the clothing system using the parallel method; Step 4: Calculate the overall thermal resistance based on the local thermal resistance of the clothing system; The heat transfer equations for the human body in step 2 include: the heat transfer equations for the parts in contact with the blanket, the heat transfer equations for the parts in contact with the air layer under the blanket, the heat transfer equations for the parts in contact with the mattress, and the heat transfer equations for the parts exposed to the external environment. The formula for calculating the heat transfer of the part in contact with the quilt is: in, This represents the total heat dissipation of the part in contact with the blanket. The surface area of the body part in contact with the blanket; and These are human skin temperature and ambient temperature, respectively. The total thermal resistance of the part in contact with the blanket; For the thermal resistance of the quilt; The dry heat transfer coefficient of the quilt surface; The formula for calculating the heat transfer of the contact area with the lower air layer is: in, This represents the total heat dissipation of the portion in contact with the lower air layer. The surface area of the part of the body in contact with the air layer; The total thermal resistance of the portion in contact with the lower air layer; The heat from the air layer beneath the blanket is first transferred to that air layer, and then transferred to the external environment through both the blanket and the mattress. The calculation formula is as follows: in, The temperature of the lower air layer; , and These are the thermal resistances for heat transfer to the air layer beneath the blanket, heat transfer through the blanket to the external environment, and heat transfer through the mattress. and These are the heat transfer areas through the quilt and mattress, respectively; and These are the dry heat transfer coefficients of the skin surface and the quilt surface, respectively, in contact with the air layer beneath the quilt. For mattress thermal resistance; The following formula is derived from the above calculation formula: therefore, in, and These are the ratios of the heat transfer area through the quilt and mattress to the surface area of the air layer; The heat transfer in the part in contact with the mattress is calculated using the following formula: in, This represents the total heat dissipation of the part in contact with the mattress. The surface area of the body in contact with the mattress; The total thermal resistance of the part in contact with the mattress; The formula for calculating heat transfer in the exposed external environment is: in, This represents the total heat dissipation of the portion exposed to the external environment. The body surface area of the parts exposed to the external environment; The total thermal resistance of the portion exposed to the external environment; The formula for calculating the local thermal resistance of the clothing system using the parallel method in step 3 is as follows: in, For local thermal resistance; This refers to the local surface area. , , , These are the ratios of the body surface area in partial contact with the blanket, in contact with the air layer under the blanket, in contact with the mattress, and exposed to the external environment to the total surface area of that part; The formula for calculating the overall thermal resistance of the clothing system in step (4) is as follows: in, The overall thermal resistance of the clothing system; The surface area of each local part; For the local thermal resistance.
2. The method for predicting the thermal resistance of a clothing system according to claim 1, characterized in that, Step 1 uses 3D virtual technology to construct a 3D geometric model of the clothing system and the sleeping human body.
3. The method for predicting the thermal resistance of a clothing system according to claim 1, characterized in that, The body parts include: head, chest, abdomen, back, buttocks, upper arm, forearm, hand, thigh, calf, and foot.
4. The method for predicting the thermal resistance of a clothing system according to claim 1, characterized in that, Step 1 further includes: denoising, repairing, and patching holes in the clothing system and the model of the sleeping human body using Geomagic image processing software.
5. The method for predicting the thermal resistance of a clothing system according to claim 1, characterized in that, Step 1 involves exporting the bedding system model and the sleeping human body model as OBJ files, fitting and aligning the processed bedding system and sleeping human body geometric models, and using the 3D comparison function to export the deviation values of the two models. This yields the ratio coefficients of the body surface area of different parts in contact with the blanket, the air layer under the blanket, the mattress, and the external environment to the total surface area of that part.
6. The method for predicting the thermal resistance of a clothing system according to claim 5, characterized in that, The bedding system model includes an inner quilt and a mattress.
7. The method for predicting the thermal resistance of a clothing system according to claim 5, characterized in that, The sleep human geometry model includes the human body and the mattress.