Study On Greenhouse Emergency Warming Wind Energy Stirring Heating Device

In recent years,China's facility agriculture industry has developed rapidly,and the greenhouse area has increased year by year.It has not only brought rich green vegetables,but also increased farmers' income.It has also played an obvious role in promoting the adjustment of China's agricultural industry structure and modern agricultural construction.China's solar greenhouse is mainly concentrated in the north temperate zone and warm temperate zone,and it needs to warm the greenhouse to meet the normal wintering growth of plants.At present,active greenhouse heating methods mainly include hot blast stoves for burning fossil energy,heating and heating of hot water heaters,which not only face the double pressure of environmental pollution and energy depletion,but also cause the problem of excessive greenhouse production costs.Therefore,the use of wind,solar,geothermal energy and other clean renewable energy for the active warming of the greenhouse is conducive to the development of facility agriculture in the direction of modernization.This paper proposes a heating system that uses the wind energy stirring heating device to warm the greenhouse,and builds a test platform for simulating the wind energy stirring heating device,and explores the number of stirring rotor layers and the distribution position and working fluid level height factors of the stirring heating device.The main research work and conclusions on the impact of heat efficiency are as follows:(1)The principle of stirring and heating and the factors affecting the heating power are analyzed in detail.The results show that the liquid working fluid inside the heater is completely turbulent and has a double circulation flow state;the heating power is proportional to the cubic density of the stirring medium,the cubic of the stirring speed,and the fifth power of the stirring rotor diameter.It is also related to the width of the blade of the stirring rotor and the number of blades.It is related to the shape and diameter of the mixing drum,and is related to the width and number of the baffle.The influence of these factors on the heating power is relatively clear.However,the influence of the number and distribution of the stirring rotor and the liquid level of the liquid working fluid on the heating power has not been studied,which is the focus of this paper.(2)The steady-state simulation study was carried out for each working condition by using FLUENT software.The velocity cloud map,velocity vector diagram and turbulence intensity map of each working condition were analyzed.The results show that the turbulent motion of the working fluid is positively correlated with the rotational speed;the fluid flow state is in full compliance with the double-circulating flow state;the flow velocity and turbulence intensity of the working fluid are significantly increased and strengthened around the agitating rotor blades;The higher the liquid level height,the smaller the air cavity.(3)A set of simulated wind energy stirring test platform with rated power of 2 kW was designed and built.The experimental research was carried out on the number of layers of the stirring rotor and its distribution position and working fluid level.The results show that the number of stirring rotor layers and their distribution position and working fluid level are important factors affecting the heating power and heating performance.Reasonable arrangement of double-layer stirring rotor compared with single-layer stirring rotor,the heating power and heating performance are significantly improved.Taking 400 r/min,the heating power is increased by 367 W,increased by 34.56%,and stirred for 70 min.The amplitude increased by 9.3 °C,and the heating rate increased by 432.45 J/s,an increase of 48.52%.The working fluid level is the best at 409 mm.Compared with the liquid level of 290 mm,the heating power is increased by 570 W,which is 69.94%.The stirring temperature is increased by 6.5 °C for 70 min.The rate increased by 302.25 J/s,which increased by 41.23%,and the total heat generated increased by 249.5.51 J,an increase of 81.03%.At the same time,the working fluid level is also an important factor affecting the heating efficiency of the mixing.The liquid level is 426 mm,the thermal efficiency is increased by 7.1231% compared with the working fluid level of 290 mm,and the heating efficiency is up to 95.8413%.