| Technological air conditioning usually includes three kinds: constant temperature and humidity air conditioning,cooling air conditioning and purifying air conditioning.The indoor temperature and humidity of constant temperature and humidity air conditioning have stricter accuracy requirements.With the development of science and economy in China,constant temperature and humidity indoor environment is also widely used in many industries,such as machinery,medicine,testing,food and other industries.Constant temperature and humidity technology requires not only precise control system,but also indoor air distribution is an important factor affecting the uniformity of temperature and humidity distribution.The velocity and temperature and humidity distribution of air distribution are influenced by the shape of the room,the form and layout of the air supply and return outlet,and the air supply volume.Therefore,it is very important for the designer to design the air distribution reasonably in the room for the constant temperature and humidity environment.Through mutual validation of experiment and numerical simulation method,the thermal and humid environment of constant temperature and humidity air-conditioning room with different air supply parameters,air return outlet layout and stabilized layer height is simulated by AIRPAK simulation software in numerical simulation calculation.The following conclusions are drawn:1.Using constant temperature and humidity air-conditioning room for experimental research,through comparative analysis with the numerical simulation results under the same conditions,the error range between the experimental data and the numerical simulation results is within the allowable range,which verifies the correctness of the numerical simulation method.2.AIRPAK is used to simulate and calculate the constant temperature and humidity air-conditioning rooms under different pressure-stabilized layer heights,supply air temperature differences and return air modes,and the numerical simulation results under different pressure-stabilized layer heights,supply air temperature differences and return air modes are compared and analyzed vertically and horizontally.3.The numerical simulation results show that the indoor temperature decreases and the relative humidity increases with the increase of the height of the stabilizer layer under the same condition of air supply temperature difference and return air.The room with constant temperature and humidity of 150 mm,200mm and 300 mm,the average indoor temperature is 19.35℃,19.28℃ and 18.98℃,and the average indoor relative humidity is 53.71%,53.98% and 54.96% respectively.With the increase of the height of the stabilized layer,the indoor temperature gradually decreases and the relative humidity gradually increases.4.The results of numerical simulation show that under the same condition of supply air temperature difference and return air,the change of the height of stabilization layer has a greater impact on the temperature and humidity of the non-working area(Z=2m or more)in the room,and a smaller impact on the temperature and humidity of the working area(Z=2m or less).When the temperature difference of supply air is 3℃and the return air mode is downward return air,the average temperature values of constant temperature and humidity room with 150 mm,200 mm and 300 mm stabilization layer height and non-working area(Z=2 m or more)are 18.32℃,18.16℃ and 17.94℃ respectively,and the average relative humidity is 57.10%,57.68% and 58.52% respectively.The average temperature values in the working area(Z=2m or less)were 20.10℃,20.08℃ and 20.06℃ respectively,and the average relative humidity values were 51.27%,51.32% and 51.39%,respectively.The variation of the voltage-stabilized layer makes the difference between the average temperature and humidity in the non-working area(Z=2m or more)bigger,that is,the influence is greater,and the difference between the average temperature and humidity in the working area(Z=2m or less)is smaller,that is,the influence is smaller.5.The numerical simulation results show that the indoor temperature decreases and the relative humidity increases with the increase of the temperature difference of the supply air under the same return air mode and the height of the stabilized layer.When the height of the stabilized layer is 200 mm and the return air mode is the downside return air,the difference of supply air temperature is 3℃,4℃,5℃ and 6℃,and the average temperature of the room with constant temperature and humidity is 19.28℃,19.04℃,18.88℃ and 18.41℃,respectively.The average relative humidity is 53.98%,54.80%,55.17% and 57.18% respectively.6.The results of numerical simulation show that the indoor temperature and relative humidity of the side return air mode are larger than those of the lower return air mode under the same conditions of the height of the stabilized layer and the temperature difference of the supply air,while the indoor temperature and relative humidity of the lower return air mode are smaller and larger.When the height of the stabilized layer is 200 mm and the temperature difference of the supply air is 3℃,the return air mode is the lower side return air and the side return air.The average temperature values of the room with constant temperature and humidity are 19.28℃ and 19.49℃ respectively,and the average relative humidity values are 53.98% and 53.31%,respectively.7.The results of numerical simulation show that when the room with constant temperature and humidity whose air supply temperature difference is 3℃,4℃,5℃ and 6℃ centigrade is subject to the change of indoor load,the time of reaching steady state after the change of indoor load is 600 s,1000s,1400 s and 2000 s,respectively.The difference between the new steady-state temperature,relative humidity and the original steady-state temperature and relative humidity is 0.07℃、-0.33%;0.26℃、-0.80%;0.45℃、-1.41% and 0.75℃、-2.34%.The smaller the difference of supply air temperature is,the shorter the time of restoring to the new steady state is under the fluctuation of indoor load in the constant temperature and humidity room,and the smaller the difference of temperature and relative humidity between the new steady state and the original steady state is;that is,the smaller the difference of supply air temperature is,the more stable the temperature and humidity environment can be maintained in the constant temperature and humidity air conditioning room. |
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