Study On Reliability Of Service Life And Heat Transfer Characteristics Of Water Conveyer In High And Cold Region

As an important special transportation vehicle,the cold water delivery truck has important strategic significance in the transportation tasks under severe conditions such as disaster relief and material transportation in high cold areas.Due to the particularity of its driving conditions on off-road roads and extremely cold and low temperature environments,the reliability of its off road running life and the research on its anti-icing and thermal insulation performance under-low temperature environments are of great significance.Based on this,this subject uses theoretical calculations and simulation analysis to systematically study the reliability and thermal insulation performance of the water tanker’s life,and provide a reference for the structural design of the water tanker in cold areas.The main research contents and conclusions of this paper are as follows:1.The road surface excitation input during the water vehicle driving process is studied.The road load spectrum under different road levels is obtained through the inverse Fourier transform method combined with the road power spectrum density function,and the calculation of the water vehicle liquid sloshing pressure is established.The finite element model applies the obtained road load spectrum in the form of a time function to the road surface constraints during vehicle driving,and sets the relevant boundary conditions to obtain the fluid pressure distribution results for normal driving,turning and braking conditions,and further establishes the fluid pressure in the form of a function,it is applied to the indirect fluid-solid coupling calculation method of the water tanker.2.Taking a certain type of water tanker as the object,a finite element model for calculating the structural strength of the water tanker was established,and the mechanical analysis and calculation under dynamic driving,turning and braking conditions were carried out,and the wing plate assembly was extracted.And analyze the cloud diagram of the stress calculation results of key parts such as the wave breaker,the sub-frame,and the tank body.The analysis results show that the stress level of the key load-bearing parts of the water tanker does not exceed the allowable stress of the materials used,which verifies the safety of the static strength design of the scheme.3.The fatigue reliability of the key parts of the water tanker is studied,the stress-time curve of the larger stress point of the wave breaker assembly is extracted,and the stress amplitude and the average stress are calculated by the rainflow counting method combined with the Matlab software program.The Goodman formula was used to correct the obtained average stress to the average stress under symmetrical cycle conditions with a stress ratio equal to-1 that can be used for fatigue calculations,and the simplified S-N curve of the material was obtained.Through the calculation of Miner’s linear cumulative damage theory,the safety factors of the wave-breaking board corresponding to the driving distance of 3 thousand kilometers,20,000 kilometers,50,000 kilometers,and 100,000 kilometers are obtained.4.The thermal insulation performance of the tank body of the water tanker under extreme cold conditions is studied,and its heat transfer method is analyzed.For the convective heat transfer that has a greater impact on heat loss,the CFD software is used to compare the outer skin of the tank and the outside air.The convective heat transfer coefficient between was calculated.Finally,according to the structural characteristics of the insulated tank,three-dimensional and two-dimensional finite element calculation models were established respectively,and thermal simulations were performed on a quarter of the tank and the heat dissipation dangerous section,and the temperature distribution and heat loss results after 24 hours were carried out.The analysis showed that the parts with more serious heat dissipation were obtained,and the results showed that the drinking water transported in the tank can still maintain above zero after 24 hours,and the design of the tank body insulation structure can meet the design requirements.