【作者】 逄学艳；

【导师】 毛华永；

【作者基本信息】 山东大学 ， 动力机械及工程， 2011， 硕士

【摘要】 随着汽车保有量的高速增长,环境污染和石油资源短缺问题日趋严重。为此,世界各国积极开展新能源汽车的研发工作。其中,天然气汽车以其排放低、抑制温室效应和摆脱对石油依赖三大特性,正在世界范围内得到普及和推广。在我国,不少城市公交和出租车有大量燃油车已经改用或者正在改用压缩天然气(CNG)或液化石油气(LPG)。作为一种独立的供热装置,燃油加热器已被广泛应用于汽车、船舶等各种运载机械在低温环境下取暖、化霜、冷启动等。随着我国燃气汽车保有量的迅速增多,开发与之相匹配的燃气加热器也势在必行。本文针对国产YJT-Q30液体天然气加热器进行了性能摸底试验,掌握了其工作规律,并在此基础上进行了性能的改进与提高试验,取得了较显著的效果。首先,使用高压空气对加热器的天然气喷射器进行了流量特性试验。对影响喷射器供气性能的各影响因素,包括喷射器喷头的孔径、孔数：喷射器座量孔及流道的孔径,供气管路的管径和管长,均做了流量随供气压力而变的试验研究。并通过相关的流量修正公式,找出满足天然气加热器功率要求的天然气供气量与供气压力的关系。然后,进行YJT-Q30天然气加热器的台架性能试验研究。由于气态燃料极易与空气混合燃烧,故不易在热交换器内壁产生积炭和烟灰,使天然气加热器热效率比燃油加热器高10%以上,且燃烧时间越长,其效率差值会越大。为了减少高温燃气因流动短路而造成的热损失,进行了在热交换器燃气出口端面增加燃气均流环试验。另外,为了削弱热辐射及传导所造成的热损失,还做了在燃烧室外加装遮热筒试验,其试验效果显著。此外,本文通过自行设计的试验装置,对国产YJT-Q系列加热器和德国同类型加热器的助燃风扇做了风扇前端面距风扇罩不同间隙时的额定电压流量特性、额定转速流量特性、以及转速特性等对比试验,并对加热器助燃风扇叶片结构和风压特性等进行了理论分析。在汽车加热器的换热系统中,循环水泵是保证液体式加热器正常供热的重要组成部分。因此最后,本文自行搭建了试验台,对国产YJT-Q系列车用加热器和德国同类型加热器所用的循环水泵进行了工作特性的试验对比分析。更多还原

【Abstract】 With the rapid growth of the number of retained motor vehicles, the problem of environmental pollution and shortage of oil resources is becoming increasingly serious. In view of this, countries around the world are committed to the work of new-energy vehicles. Therefore, natural gas vehicles are popular and promoted in the world because of its low-emission, inhibition of the greenhouse effect and independence of oil. In many cities of China, lots of fuel busses and taxies have switched or are switching to compressed natural gas (CNG) or liquefied petroleum gas (LPG). As a kind of independent heating device, fuel heaters have been widely used by automobiles, ships and other transport machinery in the cold condition for heating, defrost, cold start and so on. It is inevitable to develop gas heaters to match the gas vehicles, with the number of gas car in China increasing rapidly. Performance tests were carried out on the domestic YJT-Q30 liquid natural gas heater. According to the rules obtained from the test, corresponding improvements were made out to the heater, and the experimental results are obvious.First, some experimental researches were carried out on the gas-jets used in natural gas heater with high-pressure air. There are many factors influencing the performance of gas jet used in gas heater, such as, different pore size and pore number of the nozzle, size of metering jet and flow channel, diameter and length of gas-supply pipe and so on. The above aspects were all changed and combined with the research in many ways in our research. And then, the laws were found out which showed natural gas flow changed with the gas-supply pressure through related modified formula, which will meet the power requirements of natural gas heater.Next, experimental researches were carried out on the YJT-Q30 natural gas heater. Since gaseous fuel mixed with air is easy to burn, little of carbon distribution is produced in the interior of heater exchanger, and the thermal efficiency of gas heater can be improved by more than 10% compared with fuel heater. In order to reduce the thermal losses because of hot gas flowing in a short way, a gas current-sharing hoop was added on the exit of heater exchanger rib. In addition, a heat-protection tube was installed out of the combustion chamber so that the thermal lost during the process of heat radiation and heat exchange was diminished obviously.Moreover, the performance researches about different assembling clearance between the rotor blade and fan cover of domestic YJT-Q and Germany heater fans are carried out on the self-made experiment device including the tests of the discharge characteristic of rated voltage and rated speed, and the speed characteristic.And then it analyzed the rotor blade structure and wind pressure characteristics of combustion-improving fan on vehicle heater theoretically.Since the water circulating pump is an important part of the heat transfer system in vehicle heater, to ensure normal heating for liquid type heater. At last, the operation characteristic test and the comparative analysis on the circulating pumps of domestic YJT-Q30 heater and the same type heater of German were carried out on the self-made experiment device.更多还原