Design and Analysis of the New Engine Cover for Race Car - Lab Report Example

Topic: Design and analysis (aerodynamics) of the new engine cover for open wheel climb race car by using CFD (computational fluid dynamics) [4000 words] 1. Introduction & Literature Review (700 words) 1.1 Introduction The lab report is all about the design and analysis of a new engine cover for an open wheel climb race car. The lab work was carried out using the Computational Fluid Dynamics. The lab investigated the engine cover shape to decrease the complex airflow and drag for the car back wing so as to develop an excess downward force. Augmenting the engine cover was incorporated to regulate the complex flow due to vortices and turbulence. Enhancing the engine cover was also effected in the process of decreasing the drag. The helmet was not changed in all the Computational Fluid Dynamics as a way of analysing the forces of aerodynamics like downward force and drag. At first, the investigation will revolve around the models of turbulence like Shear Stress Transport (SST) and Spalart Allmaras (SA). These models are the best suited for the Computational Fluid Dynamics research. In practice, the Spalart Allmaras (SA) model meritoriously produce good Computational Fluid Dynamics simulations in relation to performance on the cost and stability. The model is suited for meshes without structure. However, Shear Stress Transport (SST) is on the basis of k-epsilon and k-omega baselines. K-epsilon is for the parts of the body that are a bit far from the wall while K-omega model is applicable on the parts near walls. The design model, will have a design of low level engine covers for the new car in a way of cutting down the area at the front of the car. On the basis of the nature science, the new model is created in a way of reducing the coefficient of the drag as one of the aerodynamic forces. This on the assumption that the engine cover is capable of reducing the drag as a result of a decreased area at the front of the car. The small area at the front induced by low height engine cover aids in decreasing the parts of vortices and turbulence near the engine covers and cockpits. This way, the rear wing is capable of developing an excess downward force, on condition the flow is continuous. The vital fact thus is knowledge of the best way to decrease the vortices and turbulence (complex flow). The lab was also effective in perfoming Computational Fluid Dynamics simulation on the helmet. 1.2 Literature Review This is the first design established in the process which incorpiorates the engine cover as a way of investigating the regions of flow near the cockpit in each section. The design of the second car is aimed at discovering new ways on basis of high hill engine cover. In accordance to the first simulation result, unstable airflow is developed. A high fixed engine cover is designed and analysed accordingly to cut down on the vortices and turbulence. In designing the engine cover, the assumption that the car intake assemblage takes place on the peak point of the car is taken. This is due to the fact that intake can afford a flow for the intake engine. Moreover, the shape of the headrest is optimized. In the evalution, the engine can limit the flow on condition that the headrest shape is adequate. The engine cover is usually critical as a roll bar as well as the intake of air. In any race competition, the intake of air is vital for the car to win a race. In practice, the performance of the car engine in a competition is governed by the size of the air inlet that is compared to the air volume used in the engine combustion. This is as a result of the car performance dictated by the volume of air in the engine. It is indisputable, the great amount of intake is capable of taking excess air to necessitate a better performance on the engine. On the other hand, the intake of air enlarges the area in front of the engine cover that is considered unproductive for the forces of aerodynamic of a vehicle. In this light, the designer main focus in designing the engine cover is on the best way to make the intake effective. For instance, the Formula 1 have assembled different engine cover shapes. At one time the assemblage of the parts of the intake was done on the side-pods or car engine covers. . 2. Baseline Analysis (800 words) 2.1 Baseline nose model geometry (100 words) The model engine cover is low height as the figures below illustrate. In this configuration of engine model, there is a 2D (2- dimensional) view of the cross section area of the car body. The car body engine is curve shape which is determined to create a lift (downward force) when the car is set in motion through the air flow. The engine is symmetrical to create a considerable lift on the car when it is set in motion. The rear edge of the engine is tapered to translate to a moderate flow of air that is moving on the upper and lower regions of the engine cover. Figure 1, baseline engine cover CAD model (3 views Length=500mm height=210mm width=180mm) 2.2 Baseline analysis Show with pictures and bullet points or short description what the flow is doing First the car wing creates the downward force through the difference in pressure as well as velocity at the found in the middle regions of the engine cover (Bertin, 2002). This is vital in any competition race of cars. By its feature, the engine cover provide a fast flow past the top regions of the car body as is compared to the bottom regions. This way the top region has less area of pressure and so a positive lift is achieved (Bertin, 2002). At the leading edge of the body which is the engine front area there is intersection of air division at a common point referred as ‘stagnation point’ of the engine cover. This point of stagnation is where the air flow attains zero velocity as can be measured in m/s. The dynamic pressure equates also to 0 (Zero) as is measured in Pascals. There is also considerable static pressure that is the overall pressure that acts on the moving vehicle body (Katz, 2006). Figure 2, velocity distribution over baseline engine cover (side view) The narrow strip below the slice of the car side view has variations of colours from blue on the left to red on the right. The blue colour shows the flow is of lowest magnitude while the red colour signifies a greater magnitude. As the figure above shows, the flow of the air flows at a greater velocity under the car as is compared to the top of the car. This way, thrust acting downwards is created. In this figure, it worth noting that variation in the air velocity is the most at the front of the car. Otherwise, the downward forces are evenly distributed from the front to the rear of the car. The variation in the force acting downwards is as a result of the ground clearance difference that is the difference between the body and the ground. In the same way, a large air volume circulates over and over in the inner regions of the body leading to more drag and losses in energy. Figure 3, pressure coefficient distribution over baseline engine cover (side view) Consequently, Figure 3, pressure coefficient distribution over baseline engine cover (side view) The figure shows that the pressure difference between the body rear and front is near stagnation point. This way the resultant force is equal to zero and consequently the drag force is dictated by the difference in pressure on the rear and front (Barnard, 2009). The figure has colour variations where red is for the regions with the greatest pressure overall. On the other hand, the blue colour shows the pressure is low. Accordingly, the pressure is greatest at the body front, where the air flow is 0 (zero) velocity as the pressure stagnates. In the rear parts of the body, the pressure reduces thus leading to a drag force. The other parts with the stagnation in pressure which is a high pressure are the external features, suspensions and the car tires. Thus, the resultant distribution of the pressure is a manifestation of round shape at the front which can be improved. This is possible through considering the suspended and exposed wheels which are capable of being improved in terms of aerodynamics. The downward force was also easy to induce in the same way as the drag force was. The determinant being the difference between the body top and bottom parts of the body. Figure 4, velocity vector over baseline engine cover (side view) As can be seen from the figure 4, there is a circulation at end of car (2 beams) which will produce drag for the car. The car has a larger end axle giving a larger area at the front of the car and thus, contributing significantly to the overall drag developed by the car wheels. The suspended wheels being suspended makes the air flow to act more in turbulence near the wheels on front resulting to a less defined pattern of flow. Figure 5, Pressure coefficient on baseline engine cover Figure 6, Pressure coefficient and streamline on baseline engine cover The wheels at the car front accommodate the rear wheels, because they are placed nearer the car body and are closely suspended. The suspension above is wing shaped covering an increase in the flow between the body and wheel resulting to a streamline shape flow with an area of a less pressure flow on the body of the car. This way the differences in pressure on the rear and front are reduced causing drag reduction on the back wheels. 2.3 Conclusion What problem with baseline engine cover and which part should be improve. This model is designed using aluminium spine where the inner balance is suspended and housed in the tunnel from an overhead balance (Zhang). This model is a design of ‘wheels off” meaning that its wheels are not in contact with the tunnel and this way they have their own drag being measured separately. This decreases the model complexity though it does not permit measuring in extreme conditions. The core aerodynamic parts are as follows: the diffuser, the front and the rear wings inclusive of the car engine cover. The diffuser also known as the side pod and the front wing are the only parts or devices that have endurance in very intensive advancements. This waty the car rear woings as part of the engine cover needs improvement to give a much better performance in any race. 3. 1st design engine cover (1100 words) Main change: Increase the length of engine cover which extend to the end of the car remove the beam. And change the shape of engine cover 3.1 New design objective The main objective of this is to carry out an investigation and optimization of the engine shape cover so as to reduce the complex airflow. By complex airflow reduction meaning that the vortices and turbulence flow are reduced. Therefore, the drag of the rear wing of the car body is reduced and an excess downward force is generated. This facilitates a better performance in race competition of the car. 3.2 1st design engine cover model geometry (100 words) The first engine cover model geometry was changed by adding more engine cover lengthwise. This was achieved through low height engine covers for the first design of the new car to cut the area of the front car body. The nature science is applicable in creating a more streamlined new model in the form of fast moving animals like cheetah or the fish. There was more tapering of the trailing edge (rear end) while the leading or the car front body was reduced in respect to the length. This adds the vertical component and in this way increasing the angle of attack. Figure 7, 1st design engine cover CAD model (3 views Length=632mm height=189mm width=180mm) 3.2 1st design engine cover analysis Show with pictures and bullet points or short description what the flow is doing Figure 8, velocity distribution over 1st design engine cover (side view) The designer has already adjoined the other car body parts to the car engine covers and so has reduced developing a complex airflow. The designer needs to ensure that the maximum height on the car roof is constant so that the cabin headroom is not compromised. Most important, the main part is the side pods adjoining the engine cover. The resulting shape has the shape of a fish which is streamline. This is essential in developing a trimmed car mass to penetrate more air flow for a greater velocity. Figure 9, pressure coefficient distribution over 1st design engine cover (side view) The masses in the air motion are not vital in the variation of speed. The above figure shows how the air movement is more pronounced on the car bottom than it is on the top. Figure 9, pressure coefficient distribution over 1st design engine cover (side view) Figure 10, velocity vector over 1st design engine cover (side view) Figure 11, Pressure coefficient on baseline engine cover , Figure 12, Pressure coefficient and streamline on 1st engine cover of full car 3.3 Conclusion for 1st design engine cover Conclude if objective has been met, and if design is accepted 4. 2nd design engine cover (1400 words) Main change: height of engine cover and with fin on engine cover 4.1 New design objective Say what you trying to achieve 4.2 2nd design engine cover geometry @1.Compare increase and decrease engine cover height and look the effect for car @2.Using shark fin on the engine cover and look the result Increase height of engine cover (Shape A) 1st design engine cover shape (Shape Baseline) Decrease height of engine cover (Shape C) Decrease height of engine cover with fin(Shape D) Figure 13, Different engine cover shape for test 1 and test 2 Test 1: Shape Compare the result, and we find that decrease height which has better result It has larger CL and CL/CD Because it make more flow to rear wing which can produce more downforce.   Engine cover CL Rear wing CL Car CL Engine cover CD Car CD CL/CD Increase height -0.04796  1.26522 3.28786 0.00693 1.05289 3.12270 Baseline (1st design) -0.04732  1.26881 3.29322 0.00514 1.04989 3.13673 Decrease height -0.04638  1.27222 3.29828 0.00358 1.04669 3.15114 Table 1, Compare result with different shape of engine cover Test 2: Fin   Engine cover CL Rear wing CL Car CL Engine cover CD Car CD CL/CD Decrease height -0.04638  1.27222 3.29828 0.00358 1.04669 3.15114 Decrease h with fin -0.04744  1.27498 3.30217 0.00508 1.04669 3.15486 Table 2, Compare result no fin and with fin of engine cover Final geometry Decrease height of Engine cover and with fin Figure 14, 2nd design engine cover (3 views Length=500mm height=210mm width=180mm) 4.3 2st design engine cover analysis Figure 15, velocity distribution over 2nd design engine cover (side view) Figure 16, pressure coefficient distribution over 2nd design engine cover (side view) Figure 17, velocity vector over 2nd design engine cover (side view) Figure 18, Pressure coefficient on 2nd design engine cover and rear wing Figure 19, Pressure coefficient and streamline on 2nd engine cover of full car 4.4 Conclusion for 2nd design engine cover Conclude if objective has been met, and if design is accepted Conclude the CFD result   Engine cover CL Rear wing CL Engine cover CD Baseline -0.07917 1.18633 0.03678 1st design -0.04732 1.26881 0.00514 2nd design -0.04744 1.27498 0.00508 Table 3, Compare result for baseline, 1st and 2nd design engine cover From the table shows engine cover is not primary produce downforce part for car. So we try to make it decrease the drag. Main aim for the engine cover decrease complex flow and make the smooth flow to rear wing. So the rear wing can produce more downforce. Appendix There are baseline and new design car full car model figures below that you can be used as reference. Just for you as reference. You dont need write anything for it. Baseline New design car Read More