This work was supported by the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization (grant number U1609205) and National Natural Science Foundation of China (grant number 51605443), the Key Research and Development Project of Zhejiang Province (grant number 2018C01027), the 521 Talent Project of Zhejiang Sci-Tech University, and the Young Researchers Foundation of Zhejiang Provincial Top Key Academic Discipline of Mechanical Engineering of Zhejiang Sci-tech University (grant number ZSTUME02B13).

1. Experimental rig set-up
NOTE: See Figure 1.
<ol>
	<li>Hot air blower unit
	<ol>
		<li>Ensure that the hot air blower is connected to the air nozzle through a high temperature resistant silicone pipeline that is heat-insulated with asbestos material. Gradually adjust the air nozzle to the desirable incline angle to control the air flow direction. For this work, the incline angle, &#945;, varied between 60&#176; and 90&#176;.</li>
		<l...

<ol>
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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drying+kinetics+and+quality+of+Monukka+seedless+grapes+dried+in+an+air-impingement+jet+dryer.">Drying kinetics and quality of Monukka seedless grapes dried in an air-impingement jet dryer.</a> Biosystems Engineering. 105 (2), 233-240 (2010).</li><li>Gu, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+on+optimum+temperature+value+setting+for+the+heat-setting+process+based+on+PSO.">Study on optimum temperature value setting for the heat-setting process based on PSO.</a> 3rd International Conference on Advances in Energy, Environment and Chemical Engineering. 69, (2017).</li><li>Aihua, M., Yi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+heat+transfer+coupled+with+multidimensional+liquid+moisture+diffusion+in+porous+textiles+with+a+measurable-parameterized+model.">Numerical heat transfer coupled with multidimensional liquid moisture diffusion in porous textiles with a measurable-parameterized model.</a> Numerical Heat Transfer Part A - Applications. 56 (3), 246-268 (2009).</li><li>Angelova, R. 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This section provides a few tips necessary to ensure reliable quantitative results. First, the fabric specimens must be kept completely dry to ensure the initial weights are correct. This is achievable through the drying process (i.e., using a suitable drying stove). If possible, an environment humidity that is kept constant benefits the experiment.
Secondly, the fabric specimens must be well-processed to ensure that the moisture at each region of the fabric is uniform. This can be done by man...

Impinging drying is a very effective drying method due to its high heat, mass transfer coefficient, and short drying time. It has attracted extensive attention due to its numerous applications including chemical industry, food1, textile, dyeing2, paper making3,4, etc. Now, impinging drying is widely used for its enhanced transport characteristics, especially for the drying of textiles in the heat setting process5.
Fabric is impinging dried by the nozzle array for the heat setting. Nozzle layout affects the uniformity of drying temperature, which has a significant influence on the fabric properties, drying efficiency, and on the fabric surface directly. Thus, it is necessary to understand temperature distribution on the textile surface to design a better nozzle array. There has been little investigation in this field at the present, though there has been plenty of research on heat and moisture transfer performance of the fabric drying process so far. Some research has mainly focused on the natural evaporation of a textile under a specified heat source, in which the impinging drying process was not involved in these studies6,7. Some have focused on heat and moisture transfer of the textile with hot air drying, but the textile moisture and temperature were assumed to be uniform in these studies8,9,10,11. Furthermore, a few of these studies attempted to obtain the temperature distribution variation with time for studying the heat and moisture transfer of the textile under impinging drying.
Etemoglu et al.2 developed an experimental set-up for obtaining temperature variation with the time of the fabric and total drying time, but this set-up is limited to single-point temperature measurements. The initial moisture content distribution in the fabric is also neglected in this type of research. Wang et al.12 intended to obtain temperature distribution on the fabric by pasting thermocouples on the textile surface at various points, but surface temperature distribution was not able to be accurately obtained with their method. Obtaining temperature distribution at the air impingement area on a fabric with even humidity distribution is important for industrial printing and dyeing production, and it will provide better guidance on the distribution and arrangement strategy for object drying with a multi-nozzle13. The following procedure provides details to study the heat and moisture transfer of a fabric during the impinging drying process. The initial moisture content is well-controlled to be evenly distributed, while the surface temperature at every point of the fabric is obtained via the experimental set-up.
The experimental set-up consists of a hot air blower unit, infrared thermograph unit, uniform padder system, and other auxiliary devices. The hot air blower unit supplies the hot air with a specified temperature and velocity in an adjustable direction according to the experimental requirements. The infrared thermograph unit records the temperature history of each impinging drying process; thus, the temperature at each pixel point of the recorded video can be extracted with a supporting post-processing tool. The uniform padder system controls the even distribution of moisture content at every point of the fabric. Finally, the influence of air impingement parameters on fabric drying characteristic with fabric moisture uniform control method are investigated. The process can be carried out in a reproducible fashion following the standard protocol described below.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Air Blower</td>
			<td>Zhejiang jiaxing hanglin electromechanical equipment co., Ltd.</td>
			<td>HLJT-3380-TX10A-0.55</td>
			<td>Air Volume: 900 m3/s;</td>
		</tr>
		<tr>
			<td>Anemometer</td>
			<td>KIMO</td>
			<td>MP210</td>
			<td>Measurement range: 0-40 m/s; Accuracy: &#177;0.1 m/s</td>
		</tr>
		<tr>
			<td>Drying stove</td>
			<td>Shanghai Shangyi Instrument Equipment Co., Ltd.</td>
			<td>DHG 101-0A</td>
			<td>precision: 1 &#176;C; Temperature control range:10-300 &#176;C</td>
		</tr>
		<tr>
			<td>Electronic Balance</td>
			<td>Hangzhou Wante Weighing Instrument Co., Ltd.</td>
			<td>WT1002</td>
			<td>Precision: 1 &#176;C; Range: 100 g</td>
		</tr>
		<tr>
			<td>Fabric Style Measuring Instrument</td>
			<td>SDL Atlas</td>
			<td>M293</td>
			<td></td>
		</tr>
		<tr>
			<td>Fabric Touch Tester</td>
			<td>SDLATLAS Ltd</td>
			<td></td>
			<td>Fabric thickness tester</td>
		</tr>
		<tr>
			<td>High thermal resistance board</td>
			<td>Baiqiang</td>
			<td></td>
			<td>Flame resistance, Heat resistance is greater than 200 &#176;C</td>
		</tr>
		<tr>
			<td>High-temperature resistant silicon pipeline</td>
			<td>Kamoer</td>
			<td>18#</td>
			<td>Temperature range: -60-200 &#176;C</td>
		</tr>
		<tr>
			<td>Infrared Thermogragh</td>
			<td>Hangzhou Meisheng Infrared 
			Optoelectronic Technology Co., Ltd.</td>
			<td>R60-1009</td>
			<td>Temperature measuring range: -20-410 &#176;C; Maximum measuring error: &#177;2 &#176;C</td>
		</tr>
		<tr>
			<td>Padder</td>
			<td>Yabo textile machinery co., Ltd.</td>
			<td></td>
			<td>Roller pressure: 0.03-0.8 MPa; Stable pressure; Easy adjustment</td>
		</tr>
		<tr>
			<td>Personal Computer</td>
			<td>Lenovo Group.</td>
			<td>L460</td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Sensor</td>
			<td>Taiwan TES electronic industry co., Ltd.</td>
			<td>1311A</td>
			<td>resolution: 1 &#176;C; Temperature measuring range: -50-1350 &#176;C</td>
		</tr>
	</tbody>
</table>

fabric moisture uniform control to study the influence of air impingement parameters on fabric drying characteristics

Impinging dryness is now a widely used and effective way for fabric drying due to its high heat and mass transfer coefficient. Previous studies on fabric drying have neglected the contributions of moisture uniformity and diffusion coefficient to the drying process; though, they have recently been shown to have a significant influence on drying characteristics. This report outlines a step-by-step procedure to investigate the effects of air impingement parameters on a fabric&#39;s drying characteristics by controlling the uniformity of its area moisture distribution. A hot air blower unit equipped with an angle adjustable nozzle is used to generate air flow with different velocities and temperatures while the drying process is recorded and analyzed using an infrared thermograph. In addition, a uniform padder is adapted to ensure the fabric&#39;s moisture uniformity. Impinging drying is studied under different initial conditions by changing the air flow temperature, velocity, and direction, then the applicability and suitability of the protocol are evaluated.

The data presented in Figure 2 are typical temperature contours for cotton fabric at different drying stages under the condition that air velocity and temperature at the nozzle outlet are 20.0 m/s and 120 &#176;C, respectively. It can be figured from Figure 2A,B,C,D that under the air impingement drying, temperature decays from the center to the periphery and forms sets of concentric circles. Meanwhile, temperatu...

Watch this Scientific Journal Video about Fabric Moisture Uniform Control to Study the Influence of Air Impingement Parameters on Fabric Drying Characteristics at JoVE.com

Fabric Moisture Uniform Control to Study the Influence of Air Impingement Parameters on Fabric Drying Characteristics

Presented here is a protocol that guarantees uniform distribution of initial moisture inside of a fabric and investigates the effects of hot-air thermodynamic parameters (velocity, temperature, and direction) and thickness on the fabric&#39;s drying characteristics (e.g., temperature variation) under the condition of air impingement.

Impinging dryness is now a widely used and effective way for fabric drying due to its high heat and mass transfer coefficient. Previous studies on fabric ...

This protocol provides a method for drying performance analysis based on surface temperature distribution instead of single-point temperature, which is the traditional way. As part of this, we developed a technique to obtain even moisture distribution in the fabric for investigating the drying performance of fabric and the air impingement. This method could provide insight into the drying of textiles in the heat inciting process, and it could be applied in the paper drying industry.To begin, start heating an oven to 120 degrees Celsius. Let it dry at that temperature for 30 minutes. Meanwhile, ensure that a hot air blower is connected to an air nozzle.Over the course of about 30 seconds, slowly move the air nozzle to between 60 and 90 degrees with respect to the sample position. Next, turn on the air blower fan, then supply power to the resistance wire of the heating element. Adjust the current until the desired air temperature is achieved.The nozzle and the air may be very hot. Don't touch the nozzle, and avoid directing the hot air blower directly on your body during the experiment. Next, hold an anemometer probe perpendicular to the air nozzle, and measure the air velocity.Adjust the rotation speed of the fan to reach the desired velocity. After that, cover the air nozzle with the heat insulation cover to shield the sample area during setup. Then, mount an infrared thermographic camera about a meter above the air nozzle.Connect the thermographic camera to a computer and open the instrument software. Then use a needle plate fixture to mount the standard fabric sample 30 millimeters above the air nozzle outlet. Focus the camera on the fabric.Then, set the temperature unit to degrees Celsius, the thermal radiance to 0.95, the ambient relative humidity to 50%the ambient temperature to 25 degrees Celsius, and the distance between the measured object and the camera to 1.5 meters. Next, confirm that the uniform padder system is connected to an air compressor. Start the compressor, and set its maximum output to 0.8 megapascals.Manually adjust the pressure regulators for the clamp cylinders to ensure that the pressure will be equal on both sides of the upper roller. Place a water-saturated, pre-weighed fabric sample on the upper roller and run the uniform padder. Turn off the padder afterwards, and confirm that the moisture content is even throughout the sample.Lastly, once the oven is dry, set it to the sample drying temperature. To begin preparing the fabric sample, cut a 400-millimeter-by-280-millimeter fabric square, and dry it in the oven for about three hours. Weigh the dry fabric, and then soak it in water for five minutes.Then turn on the padder and set the desired initial pressure. Lay the saturated fabric on the top roller of the uniform padder. Once the sample passes through the rollers, retrieve the sample and turn off the padder.Weigh the wet fabric sample and calculate the moisture content. If needed, dry the rollers with a paper towel, and run the fabric through the uniform padder again until the desired moisture content is achieved. Then confirm that the air blower temperature and velocity are set correctly, and that the nozzle is covered with the thermally-insulating board.Mount the sample in the needle plate fixture and start recording the sample temperature with the thermographic camera. Remove the heat-insulating cover so that the hot air impinges on the underside of the sample. Monitor the increasing fabric temperature on the computer.Once the temperature is approximately stable for at least 30 seconds, the fabric has dried to the target level. Stop recording the temperature, cover the nozzle with the heat-insulating cover, and remove the sample from the fixture. Set the target area in the video for analysis, and extract the temperature data.Navigate through the video, and save individual frames from notable points in time as pseudocolor images. Convert the saved frames to grayscale, and identify the intensity value for the fabric that is close to the hot air temperature. Binarize the grayscale images using that value as the threshold to display the dry regions.This cotton fabric showed a clear temperature decay from the center of the periphery under air-impingement drying. The center of the drying fabric reached a steady-state temperature after 20 seconds of heating. Minimal heating was observed at the edges of the impingement area.Increasing the temperature of the impinging air sped up the time to dryness, as did increasing the air velocity. The fabric thickness also significantly affected the drying time. Air impingement angles under 75 degrees substantially decreased the temperature at the drying center, and increased the time to dryness.Air impingement angles under 75 degrees also correspond to smaller impingement areas. Binarization analysis showed that a 70-degree impingement angle reduced the drying area by about 20%and a 65-degree angle reduced the area by about 40%relative to a 90-degree angle. The keys to obtaining the accurate drying performance of the seen fabric is the even distribution of the initial moisture content and the contiguous measurement of surface temperature.The research paves the way for future studies of the drying characteristics of sheet materials, such as fabric and paper.

Fabric Moisture Uniform Control to Study the Influence of Air Impingement Parameters on Fabric Drying Characteristics

Abstract